UVACTS-14-5-100 Evaluation of Trip Generation · 2008-04-25 · 1 EVALUATION OF PROCEDURES TO ESTIMATE TRIP GENERATION FOR GENERALIZED LAND USES By: Cyrus Stevenson Kump Dr. Michael

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EVALUATION OF PROCEDURES TO ESTIMATE TRIP

GENERATION FOR GENERALIZED LAND USES

By:

Cyrus Stevenson Kump

Dr. Michael J. Demetsky, Matthew C. Grimes

May 3, 2006

Research Report No. UVACTS-14-5-100 Date: May 3, 2006

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A Research Project Report For the Mid-Atlantic Universities Transportation Center (MAUTC) A U.S. DOT University Transportation Center Dr. Michael J. Demetsky Department of Civil Engineering Email: [email protected] Center for Transportation Studies at the University of Virginia produces outstanding transportation professionals, innovative research results and provides important public service. The Center for Transportation Studies is committed to academic excellence, multi-disciplinary research and to developing state-of-the-art facilities. Through a partnership with the Virginia Department of Transportation’s (VDOT) Research Council (VTRC), CTS faculty hold joint appointments, VTRC research scientists teach specialized courses, and graduate student work is supported through a Graduate Research Assistantship Program. CTS receives substantial financial support from two federal University Transportation Center Grants: the Mid-Atlantic Universities Transportation Center (MAUTC), and through the National ITS Implementation Research Center (ITS Center). Other related research activities of the faculty include funding through FHWA, NSF, US Department of Transportation, VDOT, other governmental agencies and private companies. Disclaimer: The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the information presented herein. This document is disseminated under the sponsorship of the Department of Transportation, University Transportation Centers Program, in the interest of information exchange. The U.S. Government assumes no liability for the contents or use thereof.

CTS Website Center for Transportation Studieshttp://cts.virginia.edu University of Virginia

351 McCormick Road, P.O. Box 400742Charlottesville, VA 22904-4742

434.924.6362

31. Report No. 2. Government Accession No. 3. Recipient’s Catalog No. UVACTS-14-5-100 (UVA-2004-03)

4. Title and Subtitle 5. Report Date: May 3, 2006 EVALUATION OF PROCEDURES TO ESTIMATE TRIP

GENERATION FOR GENERALIZED LAND USES

6. Performing Organization Code 7. Author(s) Cyrus Stevenson Kump, Dr. Michael J. Demetsky, Matthew C. Grimes

8. Performing Organization Report No.

9. Performing Organization and Address 10. Work Unit No. (TRAIS) Center for Transportation Studies

University of Virginia 11. Contract or Grant No. PO Box 400742 Charlottesville, VA 22904-7472

12. Sponsoring Agencies' Name and Address 13. Type of Report and Period Covered Office of University Programs, Research Innovation and Technology Administration US Department of Transportation 400 Seventh Street, SW Washington DC 20590-0001

Final Report

14. Sponsoring Agency Code 15. Supplementary Notes 16. Abstract

When planning for new growth and development, one of the challenges that local officials face is determining how much traffic will be generated

by a given land use or parcel, given that all that is known is the current zoning or potential rezoning of the land. Suppose a parcel of land is zoned

commercial for a particular county in Virginia, any number of detailed land uses is permitted under that zoning. Each of these detailed land uses will

generate a very different number of vehicle trips per day and can dramatically affect the transportation network in the future.

If the specific land use is unknown, the analyst must determine a generalized land use for the study. A generalized land use is chosen based on

the local zoning ordinance’s permissible land uses and also the prevailing mix of land uses within recently developed areas under that same zoning

classification in similar locales with similar site size and access characteristics. Real estate databases such as Computer Assisted Mass Appraisal (CAMA)

can greatly help the analyst choose the best possible generalized land uses and determine the development quantities because the database includes

information such as zoning, acreage, and building square footage of each parcel within the study area.

The purpose of this study is to investigate the procedure for estimating trip generation for generalized land uses by validating the Institute of

Transportation Engineers (ITE) method described in Chapter 6 of the ITE Trip Generation Handbook. The methodology must have a reasonable degree of

accuracy and be computationally feasible given available real estate databases such as the CAMA database. The procedure for estimating trip generation for

generalized land uses will be validated by comparing the estimated trip generation for generalized land uses to the observed trip generation for the current

land uses. The trip generation from the current uses is obtained from collecting field traffic data and also by using the 7th Edition ITE Trip Generation

Informational Report. Guidelines for localities to use Chapter 6 in the ITE Trip Generation Handbook to estimate trip ends early in the planning process

using generalized land uses, given various types of zoning, are an essential output of this project.

The procedure for estimating trip generation for generalized land uses is a simple procedure for planners to follow in the early development

stages in order to help them get a general idea of the possible number of trips a development can generate. This procedure will help planners to quickly

evaluate the extent of possible needed roadway improvements to account for increased traffic from the development, such as changing a two-lane roadway to

a four-lane roadway or implementing a signal.

17 Key Words 18. Distribution Statement Trip generation, generalized land use No restrictions. This document is available to the public.

19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price Unclassified Unclassified 94 N/A

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ACKNOWLEDGEMENTS

This project could not have been accomplished without the help of many people.

I would first like to thank my advisor, Dr. Michael J. Demetsky, who, in addition to being

Chair of the Department of Civil Engineering, agreed to be my advisor during my course

of study at the University. I would like to thank him very much for all of the guidance

throughout this project and for all of the help and support he gave me during my graduate

school experience.

I would like to thank the Mid-Atlantic Universities Transportation Center for their

funding throughout this project. I would also like to thank the Virginia Transportation

Research Council and its staff for the use of their outstanding facility and for all of their

guidance and encouragement during my time at the University. I would especially like to

thank Mr. Matt Grimes who helped to guide this project and was always available to

answer any questions. Mr. Lewis Woodson was an enormous help in gathering the

proper equipment for collecting field data, and he was always willing to have important

discussions.

I would finally like to thank my fellow transportation graduate students and the

staff at the University of Virginia School of Engineering and Applied Sciences. All of

these people helped me to get through the tough of times and the challenges I faced with

the school work, this project, and getting enough Rolling Stones tickets. All of you have

made my experience at the University one which I shall cherish and look back on with

fond memories.

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ABSTRACT

When planning for new growth and development, one of the challenges that local

officials face is determining how much traffic will be generated by a given land use or

parcel, given that all that is known is the current zoning or potential rezoning of the land.

Suppose a parcel of land is zoned commercial for a particular county in Virginia, any

number of detailed land uses is permitted under that zoning. Each of these detailed land

uses will generate a very different number of vehicle trips per day and can dramatically

affect the transportation network in the future.

If the specific land use is unknown, the analyst must determine a generalized land

use for the study. A generalized land use is chosen based on the local zoning ordinance’s

permissible land uses and also the prevailing mix of land uses within recently developed

areas under that same zoning classification in similar locales with similar site size and

access characteristics. Real estate databases such as Computer Assisted Mass Appraisal

(CAMA) can greatly help the analyst choose the best possible generalized land uses and

determine the development quantities because the database includes information such as

zoning, acreage, and building square footage of each parcel within the study area.

The purpose of this study is to investigate the procedure for estimating trip

generation for generalized land uses by validating the Institute of Transportation

Engineers (ITE) method described in Chapter 6 of the ITE Trip Generation Handbook.

The methodology must have a reasonable degree of accuracy and be computationally

feasible given available real estate databases such as the CAMA database. The procedure

for estimating trip generation for generalized land uses will be validated by comparing

the estimated trip generation for generalized land uses to the observed trip generation for

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the current land uses. The trip generation from the current uses is obtained from

collecting field traffic data and also by using the 7th Edition ITE Trip Generation

Informational Report. Guidelines for localities to use Chapter 6 in the ITE Trip

Generation Handbook to estimate trip ends early in the planning process using

generalized land uses, given various types of zoning, are an essential output of this

project.

The procedure for estimating trip generation for generalized land uses is a simple

procedure for planners to follow in the early development stages in order to help them get

a general idea of the possible number of trips a development can generate. This

procedure will help planners to quickly evaluate the extent of possible needed roadway

improvements to account for increased traffic from the development, such as changing a

two-lane roadway to a four-lane roadway or implementing a signal.

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TABLE OF CONTENTS Acknowledgements 4Abstract 5Table of Contents 7List of Tables 9List of Figures 11 CHAPTER 1: INTRODUCTION 12

1.1 Background 121.2 Problem Statement 141.3 Purpose and Scope 151.4 Study Objectives 15

CHAPTER 2: LITERATURE REVIEW 16

2.1 Trip Generation Definition 172.2 Trip Generation in Transportation Planning 182.3 Estimating Trip Generation 19

CHAPTER 3: METHODOLOGY 22

3.1 Data Collection 223.1.1 Site Identification for Field Data Collection 223.1.2 Field Data Collection 24

3.1.2.1 Preliminary Site Visits 243.1.2.2 Data Collection 26

3.1.3 Obtaining Parcel Data 263.2 Estimating Trip Generation for Generalized Land Uses 28

3.2.1 Determining the Potential Mix of Land Uses 293.2.2 Estimation of Development Quantity 293.2.3 Estimation of Trip Generation 31

3.3 Trip Generation for Current Land Uses 363.4 Local Field Trip Data 373.5 Summary 38

CHAPTER 4: RESULTS 39

4.1 Estimating Trip Generation for Generalized Land Uses Analysis 404.1.1 Rio East Professional Park (S-1) 404.1.2 Stoney Ridge Road (S-2) 424.1.3 Branchlands Boulevard (S-3) 444.1.4 Premier Circle (S-4) 454.1.5 Fontaine Research Park (S-5) 474.1.6 Hunters Way (S-6) 494.1.7 Earhart Street (S-7) 514.1.8 Cedars Court (S-8) 524.1.9 Summary 54

4.2 Trip Generation for Current Land Uses Analysis 55

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4.2.1 Rio East Professional Park (S-1) 564.2.2 Stoney Ridge Road (S-2) 574.2.3 Branchlands Boulevard (S-3) 584.2.4 Premier Circle (S-4) 594.2.5 Fontaine Research Park (S-5) 604.2.6 Hunters Way (S-6) 614.2.7 Earhart Street (S-7) 624.2.8 Cedars Court (S-8) 634.2.9 Summary 64

4.3 Field Data Analysis 654.4 Evaluation of Procedures to Estimation Trip Generation for Generalize Land

Uses 68

CHAPTER 5: GUIDELINES FOR STATE AND LOCAL PLANNERS 73

5.1 Determine Potential Mix of Land Uses 745.2 Estimate the Appropriate Development Quantity 745.3 Estimate Trips Generated by the Total Site 765.4 Test a Range of Possible Scenarios 775.5 Summary 78

CHAPTER 6: CONCLUSIONS 79 CHAPTER 7: RECOMMENDATIONS FOR FURTHER STUDY 83 REFERENCES 85 APPENDIX A TAX MAPS 86

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LIST OF TABLES

Table Page 3.1 Potential land uses for site S-1 29 3.2 Acreage, FAR, and Density calculations for S-1 30 3.3 Estimated trips for Scenario 1 from site S-1 35 3.4 Estimated trips for Scenario 2 from site S-1 36

3.5 Estimated trips generated by current land uses from site S-1 37

3.6 Current trip field counts from site S-1 38 4.1 Total trips estimated for site S-1 in Scenario 1 41 4.2 Total trips estimated for site S-1 in Scenario 2 42 4.3 Total trips estimated for site S-2 in Scenario 1 43

4.4 Total trips estimated for site S-2 in Scenario 2 44

4.5 Total trips estimated for site S-3 in Scenario 1 45 4.6 Total trips estimated for site S-3 in Scenario 2 45 4.7 Total trips estimated for site S-4 in Scenario 1 46 4.8 Total trips estimated for site S-4 in Scenario 2 47


4.10 Total trips estimated for site S-5 in Scenario 2 49 4.11 Total trips estimated for site S-6 in Scenario 1 50 4.12 Total trips estimated for site S-6 in Scenario 2 51


4.14 Total trips estimated for site S-7 in Scenario 2 52 4.15 Total trips estimated for site S-8 in Scenario 1 53

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4.16 Total trips estimated for site S-8 in Scenario 2 54 4.17 Total trips estimated for Scenario 1 and Scenario 2 55

4.18 Estimated trips generated by current land uses at site S-1 57

4.19 Estimated trips generated by current land uses at site S-2 58 4.20 Estimated trips generated by current land uses at site S-3 59

4.21 Estimated trips generated by current land uses at site S-4 60

4.22 Estimated trips generated by current land uses at site S-5 61 4.23 Estimated trips generated by current land uses at site S-6 62 4.24 Estimated trips generated by current land uses at site S-7 62 4.25 Estimated trips generated by current land uses at site S-8 63

4.26 Total trips estimated for current land uses 64

4.27 Current traffic field counts from each site 66

4.28 Total trips estimated for current land uses and actual traffic counts 68 4.29 Total trip count comparison for all the sites 70

4.30 Comparison between the avg. FAR and the FAR for the current land uses 71

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LIST OF FIGURES

Figure Page 3.1 Potential land uses for site S-1 24 3.2 Acreage, FAR, and Density calculations for S-1 32

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Chapter 1: Introduction

The issue of growth is increasingly important in many American communities, as

civic leaders and citizens alike work to find ways to ensure viable, long-term economic

prosperity while preserving historic community character. Communities are beginning to

consider innovative ideas for meeting the needs of their residents, whether for

transportation, housing, shopping, or recreation. Better coordination between

transportation and land use is one way to allow communities to plan more

comprehensively for housing, for commercial and retail uses, and for other public

services, all in the context of accessible transportation. This can mean the installation of

a new public transit line, the construction of bicycle or pedestrian paths, or the redesign

of a much-used roadway, depending on the needs of the individual community1.

Land use and transportation planning involves the evaluation and selection of

transportation facilities to serve present and future land uses. For example, the

construction of new supermarkets, shopping centers, restaurants, office space, and

residential development will require the creation or expansion of roads and other

transportation services. An inventory and analysis of existing conditions provides

information and the basis to develop forecasting tools for both the short and long term

land use/transportation planning process.

1.1 BACKGROUND

Zoning ordinances according to the Code of Virginia Title 15.2 Chapter 22 are

land use regulations and restrictions used by cities and counties throughout Virginia to

help localities improve the public health, safety, convenience, and welfare of its

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citizens2,3. In Virginia, the way in which a parcel of land may be developed is

determined by the type of zoning with which land is designated. For example, if a parcel

is zoned “commercial,” one may construct a restaurant, an office building, or a retail-

shopping store under most zoning codes. However, if it is zoned “low-density

residential,” under the same zoning codes, the owner of the land may build a single

family home or a duplex. The specific ways in which the land may be used (restaurant,

office building, retail shopping store, single family dwelling unit, or duplex) are called

detailed or specific land uses.

When planning for new growth and development, one of the challenges that local

officials face is determining how much traffic will be generated by a given land use or

parcel, given that all the local official possibly knows is the current zoning of the land.

Suppose a parcel of land is zoned commercial, for a particular county in Virginia, any

number of detailed land uses is permitted under that zoning. Each of these detailed land

uses will generate a very different number of vehicle trips per day and can dramatically

affect the transportation network in the future.

The Institute of Transportation Engineers (ITE) provides a Trip Generation

Informational Report4 which includes rates, equations, and data plots for specific land use

categories that are used in estimating trip ends for development proposals and for specific

land uses that are known before a re-zoning or site plan is approved. However, in the

earlier planning stages of development, the specific land use may not be known, yet there

is still a need to develop an approximate estimate of future trip generation. In this case,

the analyst knows nothing more than the proposed zoning classification of the parcel or

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land in question; that is, there is not a site plan available, hence, the precise quantity of

possible development and the traffic generated is unknown.

If the specific land use is unknown, the analyst must determine a generalized land

use for the study. A generalized land use is chosen based on the local zoning ordinance’s

permissible land uses and also the prevailing mix of land uses within recently developed

areas under that same zoning classification, in similar locales with similar site size and

access characteristics. Real estate databases such as Computer Assisted Mass Appraisal

(CAMA) and the Virginia Mass Appraisal Network (VamaNet) can greatly help the

analyst choose the best possible generalized land uses because they include the acreage

and building square footage of each parcel within the study area.

1.2 PROBLEM STATEMENT

The accuracy of estimating trip generation for generalized land use techniques,

described in Chapter 6 of the ITE Trip Generation Handbook5 is not known. That is,

using the recommended process to estimate trips early in the planning process relies on

an estimation of potential land use mix and density for the site, and will not necessarily

be what actually evolves. No guidelines currently exist to help engineers and planners

estimate trip generation for the generalized land uses.

1.3 PURPOSE AND SCOPE

The purpose of this study is to investigate the trip generation process for

generalized land uses by validating the Institute of Transportation Engineers (ITE)

method described in Chapter 6 of the ITE Trip Generation Handbook5. The methodology

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must have a reasonable degree of accuracy and be computationally feasible given

available real estate databases such as CAMA and VamaNet. The procedure for

estimating trip generation for generalized land uses will be validated by comparing the

estimated trip generation to the observed trip generation from the current land uses. The

trip generation from the current uses will be obtained from collecting field traffic data

and also by using the 7th Edition ITE Trip Generation Informational Report4. Guidelines

for localities to estimate trip ends early in the planning process using generalized land

uses, given various types of zoning, are an essential output of this project.

This study is limited to sites in the City of Charlottesville and Albemarle County,

Virginia, which are two of 141 localities in Virginia that maintain their own database.

The chosen sites to be investigated were mixed use sites and were also selected based on

the feasibility of collecting actual ground counts (one or two entrances/exits) on the site

to help validate the procedure for estimating trip generation for generalized land uses.

1.4 STUDY OBJECTIVES

The specific objectives of this study are as follows:

1. To examine the literature and learn from the results of past studies conducted on land

use and trip generation.

2. To develop a methodology for determining a potential land use mix for the chosen

sites based on the permissible uses found in the zoning ordinances.

3. To examine the existing development densities and land use mix in the area of the test

sites to determine adequate floor-area-ratios (FARs).

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4. To examine and use the estimation of the trip generation procedure described in

Chapter 6 of the ITE Trip Generation Handbook.

5. To collect and analyze traffic field data to help validate the procedure for estimating

trip generation for generalized land uses.

6. To develop planning guidelines for state and local planners throughout Virginia for

using the procedure to estimate trip generation for generalized land uses.

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Chapter 2: Literature Review

The first step in this study was to examine all of the literature available on

estimating trip generation. During this step, a thorough search and review of available

documents, publications, and reports involving estimating trip generation and generalized

land use was conducted. A computerized search was performed using the Transportation

Research Information Services (TRIS) database. A manual literature search was

conducted at the Virginia Transportation Research Council (VTRC) and the University of

Virginia libraries. It was found when doing this search that there is very little existing

literature on estimating trip generation which applies to the problem at hand. The results

of the literature review are summarized under the following four topics:

1. Trip generation definition

2. Trip generation in transportation planning

3. Estimating trip generation

2.1 TRIP GENERATION DEFINITION

Trip generation is the first step of the conventional four-step travel-demand

forecasting process. The purpose of trip generation estimation as seen in the NCHRP

Report 365 is to determine the number of persons or vehicle trips entering or exiting an

area of analysis6. Trip generation is functionally related to land use, in terms of the

density, location of activities, and character of the use. Typically, automobile ownership,

income, household size, density, and type of development are the specific factors that

influence the number of trips. Other factors that may also influence the number of trips

in a region is the availability of public transportation and the quality of the current

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transportation system. The best trip generation techniques thus far use disaggregate

socioeconomic data, such as households classified by vehicle ownership, family size, or

income level (low, medium, or high) 6.

As seen in the NCHRP Report 365, trip generation parameters are presented in

two formats, vehicle-trip generation rates and cross-classification trip production and

attraction rates. The first format using vehicle-trip generation rates is commonly used for

site-impact analysis and for estimation of vehicle-trips from special generators. The

source for these rates used in the NCHRP Report 365 can be found in the 5th Edition ITE

Trip Generation Informational Report7. The current edition of these rates is the 7th

Edition ITE Trip Generation Informational Report4. This informational report includes

information on trip rates during weekdays, weekends, morning and evening peak periods,

and also background traffic on adjacent streets during the morning and evening peak

periods. The second format of trip generation parameters is the cross-classification trip

production and attraction rates, which are typically used in travel-demand models. These

rates are daily person trips that include the trip purpose6. This project is going to focus

on the first format using vehicle-trip generation rates.

2.2 TRIP GENERATION IN TRANSPORTATION PLANNING

Trip generation is important in a number of phases of transportation planning and

traffic engineering studies. The studies where trip generation is necessary include:

• Regional studies that consider a range of land uses and related social and

economic characteristics.

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• Regional transportation alternatives studies and development of long-range

transportation plans.

• Short-range and long-range plans that evaluate transportation needs along a

corridor or a specific sub-area.

• Impact studies that assess the effect of new development such as a shopping

center, residential development, or industrial park (also known as site impact

analysis) 6.

The different types of studies listed above for trip generation information have resulted in

a wide range of various levels of trip generation data collection. Site-specific vehicle trip

rates are presented for impact studies where land uses are known for small areas and

vehicle rates are needed to assess the impact of the development. However, the use of

person trips is preferred for the other types of studies where the trip generation estimation

is being studied at the regional level6.

2.3 ESTIMATING TRIP GENERATION

Trip generation provides a wide range of information on the relationships between

vehicle trip generation and site characteristics. A major challenge in estimating trip

generation is for the analyst to make reasonable and responsible trip estimates for the

development in question. The ITE Trip Generation Informational Report provides

various types of data for many different land uses. Data found in the report includes: data

plots, weighted average rates, standard deviations, “best fit” curves, and regression

equations4, all of which can be used to help the analyst best estimate trip generation for

various studies. The Institute of Transportation Engineers has developed a Trip

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Generation Handbook that provides guidance in the interpretation of this data and

recommends a step-by-step procedure for developing a trip generation estimate using

Trip Generation data from the Trip Generation Informational Report5.

The 7th Edition ITE Trip Generation Informational Report is based on more than

4,250 trip generation studies submitted to ITE by public agencies, developers, consulting

firms and associations8. Some of the studies date as far back as the early 1960s, but ITE

analysts have shown that there is no significant difference between the mean trip rates of

the older data and the newer data, thus allowing the sample sizes of the given land uses to

remain maximized8.

In the 7th Edition ITE Trip Generation Informational Report, variations in trip

generation characteristics for specific land uses are reflected in the range of rates,

standard deviation, and coefficient of determination (R2) value. These variations, as

noted in the Trip Generation User’s Guide, may be due to a small sample size, individual

marketing of the site, economic conditions of the business market, geographic location of

the sites studied, or unique characteristics of the specific site8.

The Trip Generation Informational Report supplies engineers and transportation

planners with such a wide range of statistical information for the varying land uses, that it

has become a very valuable tool in smaller trip generation studies (impact studies). Even

though most engineers and planners use the Trip Generation Informational Report to help

develop their trip generation studies, some planners believe the information can be

misleading. In an article by Donald Shoup, “Roughly Right or Precisely Wrong,” he

discusses how the precision of the statistical information provided with the trip

generation rates can be misleading to transportation planners because precision implies

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certainty9. In this article Shoup emphasizes both the precision and the statistical

insignificance (low number of studies, low R2 value, etc.) in the trip generation rates at

fast food restaurants and raises the question of how many other land uses are statistically

insignificant9.

“Estimating Trip Generation for Generalized Land Uses,” is Chapter 6 of the ITE

Trip Generation Handbook. This section, developed by Brian Bochner, is based on his

own experiences and approaches that were accepted by other agencies when this section

was being developed. According to Mr. Bochner, no additional sources or references

were found or cited in this section of the ITE Trip Generation Handbook. Instead, the

development of Chapter 6 is original work10. There are no studies that have been found

which show the use of this procedure described in Chapter 6 of the ITE Trip Generation

Handbook or its effectiveness at providing reasonable and accurate trip generation

forecasts.

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Chapter 3: Methodology

The procedure developed for conducting this study consists of four main steps.

Each step plays a significant role in validating the trip generation estimation procedure

for generalized land uses described in Chapter 6 of the ITE Trip Generation Handbook.

The four steps include:

• Data Collection

• Estimating Trip Generation for Generalized Land Uses

• Trip Generation for Current Land Uses, using the ITE trip tables

• Local Field Trip Data

Throughout this Chapter, data obtained from the first site, Rio East Professional

Park (S-1) on Rio Road East, will be used to illustrate the process. The data from the

other seven sites can be found in Chapter 4, Results.

3.1 DATA COLLECTION

The first step was to collect data for each parcel within each of the study sites.

The data collection process for each parcel consisted of a variety of information.

• Site identification

• Field data (i.e. arrival and departure traffic counts)

• Parcel data

3.1.1 Site Identification for field data collection

The study site identification was accomplished using aerial photos from VDOT’s

GIS Integrator. The sites chosen for study needed to have a good mix of land uses. The

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layouts of the sites also needed to consist of only one or two entrance and exit points due

to a limited number of traffic counters (Two Jamar TRAX I Traffic Counter/Classifier)

for this project. This limited the search for possible study sites because most areas that

consist of multiple land uses have multiple entrance and exit locations.

The sites selected for study are found throughout the City of Charlottesville and

Albemarle County, Virginia. All of the sites selected are located in urban and suburban

environments except for one, Hunters Way, which is located in a more rural environment.

The traffic flow at all of the sites varies due to the number of land uses (parcels), type of

parcel, and the size of the parcel. Data was obtained for eight total sites, which are listed

below.

1. Rio East Professional Park, Rio Road East (S-1)

2. Stoney Ridge Industrial Park, Stoney Ridge Road (S-2)

3. Branchland Boulevard, US 29 North (S-3)

4. Premier Circle, US 29 North (S-4)

5. Fontaine Research Park, US 29 South (S-5)

6. Hunter’s Way, US 250 East (S-6)

7. Earhart Street, US 29 North (S-7)

8. Cedar Court, Barracks Road (S-8)

The abbreviations in parentheses will be used throughout this report to refer to

each specific site. Figure 1 below is a map showing the area where all of the sites are

located in the City of Charlottesville and Albemarle County, Virginia. Each site is made

up of groups of parcels of land, each having varying land uses.

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Figure 3.1 Map of the study sites in the City of Charlottesville and Albemarle County.

3.1.2 Field Data Collection

3.1.2.1 Preliminary Site Visits

After the sites were identified for study, a preliminary site visit was made to each

site in order to determine the feasibility of collecting field data. It was necessary to

determine the number of entrance and exit points in order to capture every vehicle

entering and leaving the site. The traffic conditions and the physical characteristics of

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43

2

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1

8

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each site were observed in order to determine if it was safe to collect data at the selected

site.

During the preliminary visit the current land uses at each site were documented.

The adjacent and surrounding land uses were also noted. The following roadway access

information for each site was collected during the preliminary visit to ensure accurate

collection of traffic information:

• Number of lanes

• Lane and shoulder widths

• Distance to adjacent intersections

• Locations of stop signs and traffic signals

• Turning lanes

• Posted speed limits

An important observation during the preliminary site visits was the recording of

the current land uses at each site. This step was very important to assure that the

collected data from the CAMA database and each property search was concurrent with

the current land use at the site. This will also help in the selection of an appropriate ITE

land use code. Some of the sites selected were not fully mature sites, where there were

some parcels that had not yet been developed (vacant land) or there were some parcels

with vacant building structures located on them (an abandoned structure or structure on

the market to be sold). As a result, parcels located within the eight chosen sites that are

currently either vacated (undeveloped) land or uninhabited building structures were not

considered as part of this study, nor used in the analysis calculations.

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3.1.2.2 Data Collection

Data collection procedures were very similar for each study site. A TRAX I

Traffic Counter/Classifier, which is capable of collecting many types of various traffic

information was used to collect volume and time-of-day data. Data was collected for

seven of the eight sites for a full 72 hours (Tuesday – Thursday) to obtain three complete

days of midweek 24 hour volume information. Due to construction near the eighth site

(S-8) only one day of traffic data was collected.

The counters were placed at a distance away from entrance/exit points to avoid

slow moving vehicles where the counter may not record the presence of a vehicle. The

location and placement of each of the counters varied according to the configuration of

the roadway at each site. Two different road tube layouts for the TRAX I were used to

adequately collect the volume information given the varying geometry of each site.

3.1.3 Obtaining Parcel Data

The individual parcel data for each land use was obtained mostly through the

Computer Assisted Mass Appraisal (CAMA) database used by the county Assessors

Office in Albemarle County. Parcel data for the City of Charlottesville was obtained

from a GIS shapefile. Both sets of data obtained from Albemarle County and the City of

Charlottesville were accomplished with the assistance of VTRC staff members and

planners in the area. During the data collection of parcel information, it was found that

the parcel information within the databases was not 100 percent complete because the

database is continually changing and being upgraded to include changes in parcel

information.

27

An on-line property search for parcels not included in the database was done to

find missing information of parcels of chosen sites being studied. The first step in

gathering the parcel information was to locate tax maps of each of the sites to find how

exactly the site was divided into individual parcels (see Appendix A for Tax Maps). A

spreadsheet of the following information was then compiled for each parcel located

within each study area.

• Name of Parcel

• Address

• Parcel Number

• Tax Map Number

• Acres

• Gross Floor Area

• Zoning

• Land Use Code

• Description of Parcel

From the Albemarle County and the City of Charlottesville databases, the average

Floor-Area-Ratio (FAR) for each zoning classification in the County and City was

identified and recorded for use in the estimation procedure. The 7th Edition ITE Trip

Generation Informational Report4 tables were also used to get weekday data for different

ITE Land Use Codes for use throughout this project.

28

3.2 ESTIMATING TRIP GENERATION FOR GENERALIZED LAND USES

The 7th Edition ITE Trip Generation Informational Report4 provides tables with

the weighted average trip generation rates, regression equations, and data plots for

specific land uses (152 total categories in the 7th Edition). These are suitable for use in

estimating trip generation for development proposals with known specific land uses

which may apply to site plan approval or special use permits.

In the early land development stages, however, there may be situations where

there is a need for an approximate estimate of future trip generation given that the

proposed specific land use is not yet identified. In this case the analyst/planner knows

nothing more than the zoning classification or the expected zoning of the land in

question; therefore, there would not be a site plan. Consequently, the precise

development quantity may not be recognized.

The estimation procedure for this project closely follows the procedure outlined in

Chapter 6 of the ITE Trip Generation Handbook5. The procedure described in Chapter 6

consists of three basic steps to the recommended estimation process.

1. Determine the potential mix (or mixes) of land uses in the site

2. Estimate the quantity of development (e.g., gross square footage, dwelling

units, acres)

3. Estimate the number of trips generated by each individual land use and for

the total site

29

3.2.1 Determining the Potential Mix of Land Uses

The fitting trip generation estimate should reflect, to the extent possible, the

specific uses within the known zoning classification. The specific uses for each site were

best determined by knowing the specific ITE land use classifications acceptable or

existing locally within the particular zoning classification. In order to determine the

potential land uses which could be placed on each site, it was important to first read the

zoning ordinance that applied to each site. Once a list of potential land uses for each site

was complete, it was necessary to select specific possible uses for the site based on

existing land uses within recently developed areas under the same zoning classification,

preferably with similar site size and access characteristics. From this step, nine potential

uses were used for site S-1 as seen in Table 3.1 below.

Zoning Land Use Land Use Code PDMC 710 General Office Building PDMC 710 General Office Building PDMC 714 Corporate Headquarters Building PDMC 715 Single Tenant Office Building PDMC 715 Single Tenant Office Building PDMC 715 Single Tenant Office Building PDMC 720 Medical-Dental Office Building PDMC 720 Medical-Dental Office Building PDMC 720 Medical-Dental Office Building

Table 3.1 Potential land uses for site S-1.

3.2.2 Estimation of Development Quantity

Typical development densities (GSF/Acre, DU/acre, or similar ratio) should be

obtained for the chosen land uses. Even though typical development densities can be

found in national publications, this project uses local densities of land uses under similar

zoning classifications. Typical development densities may vary in different parts of a

30

region; therefore, it was critical to be as locally accurate as possible in terms of density.

The local typical densities were found from the average floor-area-ratio (FAR) for every

type of land use within each zoning classification. For example, site S-1 had a zoning

classification of Planned Development Mixed Commercial (PDMC) and the coinciding

average FAR value for every site in Albemarle County with similar zoning (PDMC) is

0.247. This FAR information for each land use was found using the CAMA database.

Below is Table 3.2, which shows the acreage, FAR, and densities for site S-1.

Rio East Professional Park Land Use Sq Ft Area (A) FAR Density (D) Land Use Code Acres (KSF/acre) General Office Building 710 10000 0.465 0.247 21.516 General Office Building 710 8000 0.744 0.247 10.758 Corporate HQ Building 714 19700 0.916 0.247 21.516 Single Tenant Office Building 715 6000 0.558 0.247 10.758 Single Tenant Office Building 715 12000 0.558 0.247 21.516 Single Tenant Office Building 715 7000 0.651 0.247 10.758 Medical-Dental Office Building 720 10000 0.930 0.247 10.758 Medical-Dental Office Building 720 8000 0.744 0.247 10.758 Medical-Dental Office Building 720 10000 0.930 0.247 10.758 Total Estimation 6.493 0.247 14.344 Current Acreage Available at the Site 6.493

Table 3.2 Acreage, FAR, and Density calculations for S-1.

The density (D) is then calculated using equation (3.1) below, where the floor-

area-ratio (FAR) is 0.247, the 43,560 square feet is the conversion for one square acre,

and the Stories is the number of stories in the building (2 stories for this example shown

below). The equation below will solve for density as ksf/acre for the parcel. The result

for this example can be seen in the first row (General Office Building) in Table 3.2

above.

xStoriesFARxD ⎟⎠⎞

⎜⎝⎛=

100043560

(3.1)

31

2100043560247.0 xD ⎟

⎠⎞

⎜⎝⎛=

516.21=D acreksf /

The area (A) found as acreage is also calculated using an equation. For each

parcel within the site, an estimated square footage for the building to be placed on the

parcel must be estimated. The estimated building square footage (SF) for the first land

use (parcel) in Table 3.2 above for site S-1 is 10,000 SF. The FAR value and the number

of stories in the building remain the same (0.247 and 2 stories). The area equation (3.2)

is as follows:

StoriesFARSFA /43560//= (3.2)

2/43560/247.0/10000=A

465.0=A Acres

3.2.3 Estimation of Trip Generation

During this step of the project, two different scenarios consisting of varying land

uses and varying development quantities were tested for estimating trip generation. If

there is a strong level of uncertainty regarding the possible land use mix and the

development density for the site, it is wise for the planner to test a wider range of

scenarios with varying land use mixes and densities to get a better understanding of the

range of possible trips that may be generated by the site.

The estimation of trip generation relies heavily on the rates that are chosen

following the recommended procedure (average rates or equations) for the estimation of

32

trip generation equation. The trip generation rates should be developed in the smallest

development units possible, such as GSF instead of acres. For this project, the gross

square footage (GSF) was estimated and used for each parcel in determining the trips

generated. The recommended procedure described in the ITE Trip Generation

Handbook5 (Figure 3.2) was used to select adequate average rates and equations for each

parcel. For this project either the equation or the average rate was used even though the

figure shows that it may be necessary to sometimes collect local data for a particular

parcel.

Figure 3.2 Recommended procedure for selecting between average rate and equation.

33

The trip generation estimate in terms of total trip ends (T) per parcel is obtained

by multiplying the trip generation rate (R) times the weighted density (D) times the area

(A) as seen in equation 3.3 below.

( )RxDxAT = (3.3)

The product of density (D) and area (A) in the above equation is simply the

number of development units that match the independent variable for the assumed trip

generation rate, based either on the weighted average rate or the regression equation. For

example, in the site S-1 for the first parcel (General Office Building) of Scenario 1, the

following data was used:

• Density => 21.516 ksf/acre

• Acreage => 0.465 acres, chosen square footage = 10,000 SF

• Rate => Ln(T) = 0.77 Ln(x) + 3.65

The density and acreage were found using equations 3.1 and 3.2, and the rate was

selected based on the recommended procedure in Figure 3.2 given that the parcel was a

General Office Building (land use code 710). The recommended procedure suggests that

the regression equation be used as the trip generation rate. Therefore, the trip generation

estimate using the regression equation as a rate for this parcel is as follows:

RxDxAT =

( )( )65.377.0exp += DxALnT

( )( )65.3465.0516.2177.0exp += xLnT

227=T trips

34

Another example of this trip generation estimate procedure is one which uses the

weighted average rate as rate (R). This example can be found in the fourth parcel, Single

Tenant Office Building (land use code 715) from Scenario 1 of site S-1. The given

information for this estimate is as follows:

• Density => 10.758 ksf/acre

• Acreage => 0.558 acres, chosen square footage = 6,000 SF

• Rate => 11.57, weighted average

RxDxAT =

558.0758.1057.11 xxT =

69=T trips

The trip generation estimate (T) for each of the eight individual sites is obtained

by summing the product of the rate, density, and acres of individual land uses using

equation 3.4 below, where i corresponds to individual land uses or developments within

the site.

( )∑=i iii xAxDRT (3.4)

Using the above equation, the total estimate of trips was calculated for each site.

The total trips estimated following this procedure used both average trip rates and also

the regression equation from each land use code chosen for a typical weekday. The total

trips calculated represent the total daily trips. Other total trips calculated included the use

of the lowest trip rate, median trip rate, and highest trip rate.

Two different scenarios consisting of varying land uses and development

quantities were tested during this step of estimating trip generation. Scenario 1 included:

35

• 2 General Office Buildings (1 story and 2 story)

• 1 Corporate Headquarters Building (2 story)

• 3 Single Tenant Office Buildings (2 are 1 story and a 2 story)

• 3 Medial-Dental Office Buildings (all 1 story)

While Scenario 2 included:

• 2 General Office Buildings (1 story and 2 story)

• 1 Corporate Headquarters Building (2 story)

• 1 Day Care Center (1 story)

• 2 Single Tenant Office Buildings (both are 1 story)

• 1 High-Turnover (Sit-Down) Restaurant (1 story)

• 2 Medial-Dental Office Buildings (both are 1 story)

• Mini-Warehouse (1 story)

The following tables show the calculated trips generated for both Scenario 1 and

Scenario 2 for site S-1. These land uses in these scenarios are not the same as what

actually exists at each site.

Rio East Professional Park Land Use Total Trips Total Trips Total Trips Total Trips Land Use Code Eq./Avg. Lowest Rate Median Rate Highest RateGeneral Office Building 710 227 36 162 288 General Office Building 710 191 29 130 230 Corporate HQ Building 714 168 116 180 244 Single Tenant Office Building 715 69 32 123 214 Single Tenant Office Building 715 139 64 246 428 Single Tenant Office Building 715 81 37 144 250 Medical-Dental Office Building 720 361 232 368 505 Medical-Dental Office Building 720 289 185 295 404 Medical-Dental Office Building 720 361 232 368 505 Total Estimation 1886 962 2015 3069

Table 3.3 Estimated Trips for Scenario 1 from site S-1.

36

Rio East Professional Park Land Use Total Trips Total Trips Total Trips Total TripsLand Use Code Eq./Avg. Lowest Rate Median Rate Highest RateGeneral Office Building 710 261 43 194 346 General Office Building 710 227 36 162 288 Corporate HQ Building 714 134 92 143 195 Day Care Centers 565 396 286 458 630 Single Tenant Office Building 715 58 27 103 178 Single Tenant Office Building 715 81 37 144 250 High-Turnover Restaurant 932 890 515 1118 1722 Medical-Dental Office Building 720 181 116 184 253 Medical-Dental Office Building 720 181 116 184 253 Mini-Warehouse 151 30 15 33 52 Total Estimation 2438 1281 2724 4166

Table 3.4 Estimated Trips for Scenario 2 at from site S-1.

In the two tables above are the estimated trips generated from applying the two

different scenarios (varying land use mixes and densities) to site S-1. The “Trip

Equation/Average” column represents the estimated trips generated following the

recommended procedure outlined in the ITE Trip Generation Handbook5 for selecting the

most appropriate trip generation rate using either the average rate or equation. The “Trip

Lowest Rate, Trip Median Rate, and Trip Highest Rate” columns represent the trips

generated using the range of rates shown in the ITE Trip Generation Informational

Report5 for each land use.

3.3 TRIP GENERATION FOR CURRENT LAND USES

The estimated trip generation for current land uses also follows the recommended

procedure for selecting between trip generation average rates and equations. For each of

the current land uses, an ITE land use code, which most adequately represents the land

use, is used to determine the trip generation for each parcel. Using the existing building

square footage found for each parcel, the appropriate ITE land use code, and following

the recommended procedure for selecting a rate, the estimated trips for each of the 52 trip

37

generating land uses in all eight sites was found. Table 3.5 below shows the estimated

trips generated by the current land uses for site S-1.

Rio East Professional Park Parcel No Sq Ft Land Use Code ITE Land Use Code Equation/Rates Trips124C0 10548 344 Office Building (710) General Office Building Ln(T) = 0.77 LN(X) + 3.64 236124B1 5184 344 Office Building (710) General Office Building Ln(T) = 0.77 LN(X) + 3.65 137124B1 2455 344 Office Building (720) Medical-Dental Office Building 36.13 89 124B2 5760 344 Office Building (710) General Office Building Ln(T) = 0.77 LN(X) + 3.65 148124B3 4422 341 Medical Office (630) Clinic 31.45 139124B4 3218 341 Medical Office (720) Medical-Dental Office Building 36.13 116124B5 2711 341 Medical Office (720) Medical-Dental Office Building 36.13 98 124B6 3119 341 Medical Office (720) Medical-Dental Office Building 36.13 113124B7 3018 341 Medical Office (720) Medical-Dental Office Building 36.13 109124B8 3628 341 Medical Office (720) Medical-Dental Office Building 36.13 131124A1 5218 341 Medical Office (630) Clinic 31.45 164

Total Trips for the Current Land Uses on the Parcel 1480

Table 3.5 Estimated trips generated by current land uses from site S-1.

By following the recommended procedure, it was sometimes suggested to collect

local data for a given parcel; however, the most adequate equation or average rate was

used throughout this study. Using the 52 current land uses located within the eight total

sites, ITE land use codes were found for all but three of the current land uses. The three

land uses (parcels) which had no ITE land use code of close resemblance was a Lifecare

Medical Transport business, a Hobbies and Collectibles shop, and a Hair Salon & Spa

business. For these three land uses, each site was observed very closely to predict the

actual trips generated for each of the parcels.

3.4 LOCAL FIELD TRIP DATA

Traffic counts were collected for each of the eight sites. The data was collected

for three days during the middle of the week for a typical trip count (Tuesday,

38

Wednesday, or Thursday) and then an average trip count was calculated for the three

days. The trips were collected using a TRAX I Traffic Counter/Classifier. Two different

tube layouts were use to collect the necessary data given the geometries of the sites.

Table 3.6 below shows the actual traffic counts for the Rio East Professional Park site (S-

1).

Actual 24-hour field Traffic Counts on a Weekday

Site Location Date

RecordedEntering

Trips ExitingTrips

Total Trips

Average Trips

Rio East Professional Park 8/9/2005 972 962 1934 Rio East Professional Park 9/14/2005 891 887 1778 1828 Rio East Professional Park 9/15/2005 891 882 1773

Table 3.6 Current trip field counts from site S-1.

The collection of actual traffic field counts for arriving and departing vehicles for

each site will help to validate the procedure used for estimating trip generation for

generalized land uses.

3.5 SUMMARY

The methodology for this project closely follows the procedure for “Estimating

Trip Generation for Generalized Land Uses” described in Chapter 6 of the ITE Trip

Generation Handbook5. The procedure for estimating trip generation for generalized land

uses used in this methodology was applied to all eight sites, and the estimated total trips

were then calculated assuming the sites were either undeveloped land or going to be

totally redeveloped. When the estimation procedure was completed, the trip generation

for current uses and the traffic field counts for each site were then collected to help in

testing the accuracy of this estimation procedure. The results and evaluations of this

methodology can be seen in the following chapter of this report.

39

Chapter 4: Results

The results of this study are divided into the following categories:

• Estimating Trip Generation for Generalized Land Uses Analysis

• Trip Generation for Current Land Uses Analysis

• Local Field Trip Data Analysis

• Evaluation of Procedure to Estimate Trip Generation for Generalized Land

Uses

The first section will discuss the results found from using the procedure to

estimate trip generation for generalized land uses. It will examine the two scenarios

chosen for each of the eight sites as well as the varying land use mixes and densities to

show the effects on the number of trips generated.

The second section will discuss the current land uses that exist at each site and

analyze the number of trips that should be generated according to the average rates and

equations in the 7th Edition ITE Trip Generation Informational Report4 and the given

parcel data (land use, building square footage, etc.). Also, any possible assumptions or

predictions that may have been made during the analysis of each site will be discussed.

The third section will review the results from the field data collected from each

site. This section will include field observations from each site and analyze the collected

vehicle trip counts for the existing land uses (parcels).

The fourth section of this chapter will provide an overall analysis and evaluation

of the procedure to estimate trip generation for generalized land uses using the results

from the previous three sections. This analysis and evaluation will use the collected

results to validate the estimation procedure used.

40

4.1 ESTIMATING TRIP GENERATION FOR GENERALIZED LAND USES

ANALYSIS

When analyzing the procedure for estimating trip generation for generalized land

uses, as described in Section 3.2 of this report, it is necessary to review each of the eight

sites individually. Throughout this section, all of the assumptions made for Scenario 1

and Scenario 2 for each site are discussed. The two scenarios again represent the varying

range of possible land use mixes and densities for each of the sites. The tables

throughout this section will include information used for the estimation of trip generation.

This information includes:

• Selected land uses based on permissible uses (within known zoning classification)

• Estimated square footage of each of the selected parcels

• Calculated Area (acres) for each parcel

• Average FAR for the particular zoning classification

• Calculated Density (GSF/acre) for each parcel

• Total estimated trips using either the average rates or equations

4.1.1 Rio East Professional Park (S-1)

The Rio East Professional Park site is located in Albemarle County north of the

City of Charlottesville, adjacent to Rio Road. The site is 6.493 acres and is zoned

Planned Development Mixed Commercial (PDMC), having a corresponding average

FAR of 0.247 for all other parcels with similar zoning. Similar land uses were selected

for each of the two scenarios. Scenario 1 consists of nine office building land uses, while

Scenario 2 consists of seven office buildings, one daycare center, one high-turnover

41

restaurant, and a mini-warehouse. Each of the selected land uses for both scenarios has

varying estimated square footages of the buildings to be placed on them. Based on the

estimated building square footage, the calculated area (acreage) and the density can be

seen in Table 4.1 and Table 4.2 below. The calculated density varies due to the story

height. Three land uses in the first scenario are two stories, while only two land uses in

the second scenario are two stories. All others are one story land uses.

The total estimated trips generated, seen in the tables below, were calculated

using either the recommended average rate or the equation found from following the

diagram in Figure 3.1, taken from the ITE Trip Generation Handbook5. The total

estimated trips generated in Scenario 1 are 1,886 trips and the total estimated trips

generated for Scenario 2 are 2,438 trips. The trips generated in both scenarios were very

similar; however, the increased trips generated in Scenario 2 were due to the addition of

the day care center and the high-turnover restaurant. The following tables provide the

estimated trip generation for both Scenario 1 and 2 of the Rio East Professional Park site

(S-1).

Rio East Professional Park Land Use Sq Ft

Area (A) FAR

Density (D)

Total Trips

Land Use Code Acres (KSF/acre) Eq./Avg. General Office Building 710 10000 0.465 0.247 21.516 227 General Office Building 710 8000 0.744 0.247 10.758 191 Corporate HQ Building 714 19700 0.916 0.247 21.516 168 Single Tenant Office Building 715 6000 0.558 0.247 10.758 69 Single Tenant Office Building 715 12000 0.558 0.247 21.516 139 Single Tenant Office Building 715 7000 0.651 0.247 10.758 81 Medical-Dental Office Building 720 10000 0.930 0.247 10.758 361 Medical-Dental Office Building 720 8000 0.744 0.247 10.758 289 Medical-Dental Office Building 720 10000 0.930 0.247 10.758 361 Total Estimation 6.493 0.247 14.344 1886 Current Acreage Available at the Site 6.493

Table 4.1 Total trips estimated for site S-1 in Scenario 1

42

Rio East Professional Park Land Use Sq Ft

Area (A) FAR

Density (D)

Total Trips

Land Use Code Acres (KSF/acre) Eq./Avg. General Office Building 710 12000 0.558 0.247 21.516 261 General Office Building 710 10000 0.930 0.247 10.758 227 Corporate HQ Building 714 15700 0.730 0.247 21.516 134 Day Care Centers 565 5000 0.465 0.247 10.758 396 Single Tenant Office Building 715 5000 0.465 0.247 10.758 58 Single Tenant Office Building 715 7000 0.651 0.247 10.758 81 High-Turnover Restaurant 932 7000 0.651 0.247 10.758 890 Medical-Dental Office Building 720 5000 0.465 0.247 10.758 181 Medical-Dental Office Building 720 5000 0.465 0.247 10.758 181 Mini-Warehouse 151 12000 1.115 0.247 10.758 30 Total Estimation 6.493 0.247 12.909 2438 Current Acreage Available at the Site 6.493


4.1.2 Stoney Ridge Road (S-2)

The Stoney Ridge Road site is located in Albemarle County south of the City of

Charlottesville, off of the Avon Street Extension. The site is 27.590 acres and is zoned

Planned Unit Development (PUD), having a corresponding average FAR of 0.140 for all

other parcels with similar zoning. Similar land uses were selected for each of the two

scenarios. Scenario 1 consists of one manufacturing land use, two warehousing land

uses, one day care center, four office building land uses, and one building materials and

lumber store. Scenario 2 consists of one manufacturing land use, one warehousing land

uses, one residential condominium/townhouse complex (30 units), five office building

land uses, and one building materials and lumber store. Each of the selected land uses for

both scenarios has varying estimated square footages of the buildings to be placed on

them. Based on the estimated building square footage, the calculated area (acreage) and

the density can be seen in Table 4.3 and Table 4.4 below for each parcel. The calculated

density varies due to the story height. Only one of the land uses in the first scenario is

43

two stories, while in the second scenario there are two land uses, which are two stories.

All others are one story land uses.





generated for Scenario 2 are 1,493 trips. The trips generated in both scenarios were fairly

similar, given the varying land uses and building square footages. The following tables

provide the estimated trip generation for both Scenario 1 and 2 of the Stoney Ridge Road

site (S-2).

Stoney Ridge Road Land Use Sq Ft

Area (A) FAR

Density (D)

Total Trips

Land Use Code Acres (KSF/acre) Eq./Avg. Manufacturing 140 35000 5.747 0.140 6.090 115 Warehousing 150 30000 4.926 0.140 6.090 461 Warehousing 150 41010 6.734 0.140 6.090 501 Day Care Centers 565 5000 0.821 0.140 6.090 396 General Office Building 710 4000 0.657 0.140 6.090 112 General Office Building 710 6000 0.985 0.140 6.090 153 Corporate HQ Building 714 20000 1.642 0.140 12.179 170 Single Tenant Office Building 715 25000 4.105 0.140 6.090 289 Building Mat. & Lumber Store 812 12000 1.971 0.140 6.090 542 Total Estimation 27.590 0.140 6.766 1662 Current Acreage Available at the Site 27.590


44

Stoney Ridge Road Land Use Sq Ft

Area (A) FAR

Density (D)

Total Trips

Land Use Code Acres (KSF/acre) Eq./Avg. Manufacturing 140 40510 6.652 0.140 6.090 136 Warehousing 150 35000 5.747 0.140 6.090 479 Residential Condo/Town. 230 30000 4.926 0.140 6.090 231 Corporate HQ Building 714 13000 1.067 0.140 12.179 112 General Office Building 710 6000 0.985 0.140 6.090 153 General Office Building 710 7000 1.149 0.140 6.090 172 Corporate HQ Building 714 20000 1.642 0.140 12.179 170 Single Tenant Office Building 715 18000 2.956 0.140 6.090 208 Building Mat. & Lumber Store 812 15000 2.463 0.140 6.090 677 Total Estimation 27.590 0.140 7.443 1493 Current Acreage Available at the Site 27.590


4.1.3 Branchlands Boulevard (S-3)

The Branchlands Boulevard site is located in Albemarle County north of the City

of Charlottesville, adjacent to US Route 29. The site is 9.074 acres and is zoned Planned

Unit Development (PUD), having a corresponding average FAR of 0.140 for all other

parcels with similar zoning. Varying land uses were selected for each of the two

scenarios. Scenario 1 consists of one motel land use, one specialty retail center land use,

and one high-turnover restaurant land use, while Scenario 2 consists of one office

building land use, one supermarket land use, one high turnover restaurant land use and

one hotel land use. Each of the selected land uses for both scenarios has varying

estimated square footages of the buildings to be placed on them. Based on the estimated

building square footage, the calculated area (acreage) and the density can be seen in

Table 4.5 and Table 4.6 below for each parcel within the site. The calculated density

varies due to the story height. Two of the land uses in the first scenario are two stories,

while in the second scenario there is one land use, which is three stories, and one land use

that is only two stories. All others are one story land uses.

45





generated for Scenario 2 are 3,426 trips. The trips generated in both scenarios were


provide the estimated trip generation for both Scenario 1 and 2 of the Branchlands

Boulevard site (S-3).

Branchlands Boulevard Land Use Sq Ft

Area (A) FAR

Density (D)

Total Trips

Land Use Code Acres (KSF/acre) Eq./Avg. Motel 320 55000 4.516 0.140 12.179 329 Specialty Retail Center 814 41510 3.408 0.140 12.179 1840 High-Turnover Restaurant 932 7000 1.149 0.140 6.090 890 Total Estimation 9.074 0.140 10.149 3059 Current Acreage Available at the Site 9.074


Branchlands Boulevard Land Use Sq Ft

Area (A) FAR

Density (D)

Total Trips

Land Use Code Acres (KSF/acre) Eq./Avg. General Office Building 710 36850 3.026 0.140 12.179 618 Supermarket 850 20000 3.284 0.140 6.090 2045 High-Turnover Restaurant 932 6000 0.985 0.140 6.090 763 Hotel 310 32500 1.779 0.140 18.269 266 Total Estimation 9.074 0.140 10.657 3426 Current Acreage Available at the Site 9.074


4.1.4 Premier Circle (S-4)

The Premier Circle site is located in Albemarle County north of the City of

Charlottesville, adjacent to US Route 29. The site is 6.350 acres and is zoned

46

Commercial (C1), having a corresponding average FAR of 0.216 for all other parcels

with similar zoning. Varying land uses were selected for each of the two scenarios.

Scenario 1 consists of one motel land use, one specialty retail center land use, and one

high turnover restaurant land use, while Scenario 2 consisted of two office building land

uses, one new car sales land use, and one high turnover restaurant land use. Each of the

selected land uses for both scenarios has varying estimated square footages of the

buildings to be placed on them. Based on the estimated building square footage, the

calculated area (acreage) and the density can be seen in Table 4.7 and Table 4.8 below for

each parcel within the site. The calculated density varies due to the story height. There

is one land use in both the first and second scenarios that is two stories. All others are

one story land uses.






extremely similar for this site, given the varying land uses and building square footages.

The following tables provide the estimated trip generation for both Scenario 1 and 2 of

the Premier Circle site (S-4).

Premier Circle Land Use Sq Ft

Area (A) FAR

Density (D)

Total Trips

Land Use Code Acres (KSF/acre) Eq./Avg. Motel 320 55000 2.925 0.216 18.804 329 Specialty Retail Center 814 26200 2.787 0.216 9.402 1161 High-Turnover Restaurant 932 6000 0.638 0.216 9.402 763 Total Estimation 6.350 0.216 12.536 2253 Current Acreage Available at the Site 6.350


47

Premier Circle Land Use Sq Ft

Area (A) FAR

Density (D)

Total Trips

Land Use Code Acres (KSF/acre) Eq./Avg. Corporate HQ Building 714 35000 1.861 0.216 18.804 293 General Office Building 710 15000 1.595 0.216 9.402 310 New Car Sales 841 20200 2.149 0.216 9.402 673 High-Turnover Restaurant 932 7000 0.745 0.216 9.402 890 Total Estimation 6.350 0.216 11.752 2166 Current Acreage Available at the Site 6.350


4.1.5 Fontaine Research Park (S-5)

The Fontaine Research Park site is located in Albemarle County west of the City

of Charlottesville, adjacent to the Business US Route 29. The site is 67.803 acres and is

zoned Commercial Office (CO), having a corresponding average FAR of 0.172 for all

other parcels with similar zoning. Similar land uses were selected for each of the two

scenarios. Scenario 1 consists of one hotel land use, one day care center land use, one

hospital land use, and seven office building land uses. Scenario 2 on the other hand

consists of two hotel land uses, one day care center land use, one hospital land use, two

office building land uses, and one warehouse land use. Each of the selected land uses for

both scenarios has varying estimated square footages of the buildings to be placed on

them. Based on the estimated building square footage, the calculated area (acreage) and

the density can be seen in Table 4.9 and Table 4.10 below for each parcel within the site.

The calculated density varies due to the story height and each of the scenarios has a wide

range of story heights (1-4 stories) selected for this particular site as seen in the tables

below.



48



generated for Scenario 2 are 11,860 trips. The trips generated in both scenarios are

similar; however, the warehousing land use in the second scenario had a big effect

causing a lower number of trips generated because a warehouse takes up a large land area

and is not a larger trip generating land use. Another noticeable difference in the two

scenarios is that the first scenario has four more office building land uses (parcels) than

the second scenario. The following tables provide the estimated trip generation for both

Scenario 1 and 2 of the Fontaine Research Park (S-5).

Fontaine Research Park Land Use Sq Ft

Area (A) FAR

Density (D)

Total Trips

Land Use Code Acres (KSF/acre) Eq./Avg. Hotel 310 150000 6.679 0.172 22.460 1226 Day Care Centers 565 5000 0.668 0.172 7.487 396 Hospital 610 120000 4.007 0.172 29.946 3411 General Office Building 710 195000 6.512 0.172 29.946 2231 General Office Building 710 50000 6.679 0.172 7.487 782 Corporate HQ Building 714 180000 12.021 0.172 14.973 1432 Single Tenant Office Building 715 38000 5.076 0.172 7.487 440 Single Tenant Office Building 715 50000 6.679 0.172 7.487 579 Medical-Dental Office Building 720 45860 6.126 0.172 7.487 1657 Research & Develop. Center 760 200000 13.357 0.172 14.973 1780 Total Estimation 67.803 0.172 14.973 13934 Current Acreage Available at the Site 67.803


49

Fontaine Research Park Land Use Sq Ft

Area (A) FAR

Density (D)

Total Trips

Land Use Code Acres (KSF/acre) Eq./Avg. Hotel 310 150000 6.679 0.172 22.460 1226 Day Care Centers 565 10000 1.336 0.172 7.487 793 Hospital 610 200000 13.357 0.172 14.973 4211 Hotel 310 180000 12.021 0.172 14.973 1471 General Office Building 710 187830 8.363 0.172 22.460 2168 Corporate HQ Building 714 150000 10.018 0.172 14.973 1200 Warehousing 150 120000 16.029 0.172 7.487 792 Total Estimation 67.803 0.172 14.973 11860 Current Acreage Available at the Site 67.803


4.1.6 Hunters Way (S-6)

The Hunters Way site is located in Albemarle County east of the City of

Charlottesville, adjacent to the US Route 250. The site is 38.659 acres, where 4.083

acres of the site is zoned Highway Commercial (HC) and the rest of the site is zoned

Light Industrial (LI). The corresponding average FAR (0.172) for the Light Industrial

zoning category was selected to be used for the entire site because a large majority of the

site is zoned Light Industrial. Similar land uses were selected for each of the two

scenarios. Scenario 1 consists of two warehousing land uses, one mini-warehouse land

use, and five office building land uses. Scenario 2 on the other hand consists of two

warehousing land uses, three office building land uses, one mini-warehouse land use, and

one low-rise apartment complex (124 units). Each of the selected land uses for both

scenarios has varying estimated square footages of the buildings to be placed on them.

Based on the estimated building square footage, the calculated area (acreage) and the

density can be seen in Table 4.11 and Table 4.12 below for each parcel within the site.

The calculated density varies due to the story height. In the first scenario there is one

50

three-story building and two two-story buildings, whereas in the second scenario there is

only one two-story building.






similar; however, the larger amount of office building square footage in the first scenario

caused the number of trips generated to be roughly 600 trips more than the second

scenario. The following tables provide the estimated trip generation for both Scenario 1

and 2 of the Hunters Way (S-6).

Hunters Way Land Use Sq Ft

Area (A) FAR

Density (D)

Total Trips

Land Use Code Acres (KSF/acre) Eq./Avg. Warehousing 150 130000 17.380 0.172 7.480 829 Warehousing 150 20000 2.674 0.172 7.480 424 Mini-Warehouse 151 55830 7.464 0.172 7.480 140 General Office Building 710 25000 1.671 0.172 14.960 852 General Office Building 710 18000 2.406 0.172 7.480 459 Single Tenant Office Building 715 40000 1.783 0.172 22.440 463 Single Tenant Office Building 715 23000 3.075 0.172 7.480 266 Research & Develop. Center 760 33000 2.206 0.172 14.960 406 Total Estimation 38.659 0.172 11.220 3838 Current Acreage Available at the Site 38.659


51

Hunters Way Land Use Sq Ft

Area (A) FAR

Density (D)

Total Trips

Land Use Code Acres (KSF/acre) Eq./Avg. Warehousing 150 50000 6.685 0.172 7.480 534 Warehousing 150 27000 3.610 0.172 7.480 450 Corporate HQ Building 714 50000 6.685 0.172 7.480 414 Mini-Warehouse 151 70000 9.358 0.172 7.480 175 General Office Building 710 10165 1.359 0.172 7.480 229 General Office Building 710 20000 2.674 0.172 7.480 386 Low-Rise Apartment 221 124000 8.289 0.172 14.960 1022 Total Estimation 38.659 0.172 8.548 3211 Current Acreage Available at the Site 38.659


4.1.7 Earhart Street (S-7)

The Earhart Street site is located in the City of Charlottesville, adjacent to US

Route 29. The site is 1.460 acres and is zoned Mixed Use Corridor (MUC), having a

corresponding average FAR of 0.306 for all other parcels with similar zoning. Varying

land uses were selected for each of the two scenarios. Scenario 1 consists of two office

building land uses, while Scenario 2 consists of one mini-warehouse land use and one

office building land use. Each of the selected land uses for both scenarios has varying

estimated square footages of the buildings to be placed on them. Based on the estimated

building square footage, the calculated area (acreage) and the density can be seen in

Table 4.13 and Table 4.14 below for each parcel within the site.




estimated trips generated in Scenario 1 are 336 trips and the total estimated trips

generated for Scenario 2 are 279 trips. The trips generated in both scenarios were fairly


52

provide the estimated trip generation for both Scenario 1 and 2 of the Earhart Street site

(S-7).

Earhart Street Land Use Sq Ft

Area (A) FAR

Density (D)

Total Trips

Land Use Code Acres (KSF/acre) Eq./Avg. General Office Building 710 10000 0.749 0.306 13.343 227 Single Tenant Office Building 715 9480 0.711 0.306 13.343 110 Total Estimation 1.460 0.306 13.343 336 Current Acreage Available at the Site 1.460


Earhart Street Land Use Sq Ft

Area (A) FAR

Density (D)

Total Trips

Land Use Code Acres (KSF/acre) Eq./Avg. Mini-Warehouse 151 7500 0.562 0.306 13.343 19 General Office Building 710 11980 0.898 0.306 13.343 260 Total Estimation 1.460 0.306 13.343 279 Current Acreage Available at the Site 1.460


4.1.8 Cedars Court (S-8)

The Cedars Court site is located in the City of Charlottesville, adjacent to

Barracks Road. The site is 9.162 acres and is zoned Mixed Use Corridor (MUC), having

a corresponding average FAR of 0.306 for all other parcels with similar zoning. Varying

land uses were selected for each of the two scenarios. Scenario 1 consists of one mini-

warehouse land use, one residential condominium/townhouse complex (96 units), and

three office building land uses. Scenario 2 consists of one low-rise apartment complex

(124 units) and two office building land uses. Each of the selected land uses for both

scenarios has varying estimated square footages of the buildings to be placed on them.

Based on the estimated building square footage, the calculated area (acreage) and the

density can be seen in Table 4.15 and Table 4.16 below for each parcel within the site.

53

The calculated density varies slightly in the second scenario due to the story height (two-

story) of the low-rise apartment complex.




estimated trips generated in Scenario 1 are 1491 trips and the total estimated trips

generated for Scenario 2 are 1858 trips. When looking at the trips generated for this site,

the total trips generated in each scenario are not as closely related. One cause of this may

be due to the low-rise apartments having a slightly higher density in the second scenario,

producing a larger number of trips. The following tables provide the estimated trip

generation for both Scenario 1 and 2 of the Cedars Court site (S-8).

Cedars Court Land Use Sq Ft

Area (A) FAR

Density (D)

Total Trips

Land Use Code Acres (KSF/acre) Eq./Avg. Mini-Warehouse 151 30000 2.248 0.306 13.343 75 Residential Condo/Town. 230 25000 1.874 0.306 13.343 198 General Office Building 710 15000 1.124 0.306 13.343 310 Corporate HQ Building 714 35250 2.642 0.306 13.343 295 Medical-Dental Office Building 720 17000 1.274 0.306 13.343 614 Total Estimation 9.162 0.306 13.343 1491 Current Acreage Available at the Site 9.162


Cedars Court Land Use Sq Ft

Area (A) FAR

Density (D)

Total Trips

Land Use Code Acres (KSF/acre) Eq./Avg. Low-Rise Apartment 221 96000 3.597 0.306 26.685 879 General Office Building 710 48000 3.597 0.306 13.343 758 Corporate HQ Building 714 26250 1.967 0.306 13.343 221 Total Estimation 9.162 0.306 17.790 1858 Current Acreage Available at the Site 9.162


54

4.1.9 Summary

The procedure used for estimating trip generation for generalized land uses

analysis was similar for each of the eight sites. The choice of potential land uses is a key

component in this procedure. The selection of potential land uses for each site were

chosen from those land uses available in the ITE Trip Generation Informational Report

which most adequately reflected the specific uses within the known zoning classification.

Using the local FAR values of each zoning classification to calculate the area and density

of each land use at every site allows the site to be evaluated in a manner consistent with

the local trends.

In Table 4.17 below, the total estimated trips for Scenario 1 and Scenario 2 for

each study site can be seen. Scenario 1 and Scenario 2 represent varying potential land

uses and development densities, which can be placed on the site. The percent difference

shown in the table is the percent difference between the total estimated trips for Scenario

1 and Scenario 2 for each site. The percent difference in the total trips estimated for each

site is due mostly to the selected land uses to be placed on the site within the two

different scenarios. The selected land uses to be placed on the site and their

corresponding trip generation rates have the greatest effect on the total estimated trips for

each site.

55

Estimation Procedure Percent Site Name Site Area Total Trips Total Trips Difference

Scenario 1 Scenario 2 Rio East Professional Park 6.493 1886 2438 22.64 Stoney Ridge Road 27.590 1662 1493 11.32 Branchlands Boulevard 9.074 3059 3426 10.71 Premier Circle 6.350 2253 2166 4.02 Fontaine Research Park 67.803 13934 11860 17.49 Hunters Way 38.659 3838 3211 19.53 Earhart Street 1.460 336 279 20.43 Cedars Court 9.162 1491 1858 19.75

Table 4.17 Total trips estimated for Scenario 1 and Scenario 2

The procedure used for estimating trip generation for generalized land uses

proved to be a simple estimation procedure to attain total vehicle trip counts for each site.

Using the two different scenarios allowed for a range of potential land uses and densities

to be analyzed. In looking at the percent difference between the two scenarios, one can

see that the estimated trips for each scenario are very similar.

4.2 TRIP GENERATION FOR CURRENT LAND USES ANALYSIS

This section examines and analyzes the number of trips that should be generated

according to the 7th Edition ITE Trip Generation Informational Report4 and the given

parcel data (land use, building square feet, etc.). When evaluating the trip generation of

the current uses, an ITE land use code, which most adequately represents the land use,

was selected and the most appropriate rate (average rate or equation) was used to

determine the trip generation for each parcel. Each of the eight sites is analyzed

individually to account for any assumptions that may have been made. Parcels within

some of the sites that were either undeveloped (vacant land) or had uninhabited structures

(empty buildings) on them, were not used in the analysis of this study. The tables

56

throughout this section will include information used for the estimation of trip generation

for the current land uses. This information includes:

• Parcel number (according to Tax Map)

• The current square footage of the structure on the parcel

• The current land use code (according to local assessor)

• Corresponding ITE land use code

• The selected average rate or equation used to estimated trip generation

• The total estimated trips generated by the current uses

4.2.1 Rio East Professional Park (S-1)

The Rio East Professional Park site currently consists of 11 structures (land uses)

located within the site that are trip generating. The current land uses in the site are

outlined in Table 4.18 below. Using the current land use codes and conducting a site

visit, a corresponding ITE land use code, which most closely represents the land use, was

found for each parcel within the site. The total estimated trips generated, seen in the

tables below, were calculated using either the recommended average rate or the equation

found from following the diagram in Figure 3.1, taken from the ITE Trip Generation

Handbook5. The total trips generated from the 11 current land uses at the Rio East

Professional Park site are 1,480 trips.

57

Parcel No Sq Ft Land Use Code ITE Land Use Code Equation/Rates Trips124C0 10548 344 Office Building (710) General Office Building Ln(T) = 0.77 LN(X) + 3.65 236124B1 5184 344 Office Building (710) General Office Building Ln(T) = 0.77 LN(X) + 3.65 137124B1 2455 344 Office Building (720) Medical-Dental Office Building 36.13 89 124B2 5760 344 Office Building (710) General Office Building Ln(T) = 0.77 LN(X) + 3.65 148124B3 4422 341 Medical Office (630) Clinic 31.45 139124B4 3218 341 Medical Office (720) Medical-Dental Office Building 36.13 116124B5 2711 341 Medical Office (720) Medical-Dental Office Building 36.13 98 124B6 3119 341 Medical Office (720) Medical-Dental Office Building 36.13 113124B7 3018 341 Medical Office (720) Medical-Dental Office Building 36.13 109124B8 3628 341 Medical Office (720) Medical-Dental Office Building 36.13 131124A1 5218 341 Medical Office (630) Clinic 31.45 164


Table 4.18 Estimated trips generated by current land uses at site (S-1)

4.2.2 Stoney Ridge Road (S-2)

The Stoney Ridge Road site currently consists of eight structures (land uses)




found for each parcel within the site except for one. The current land use that did not

have a similar ITE land use code was a Lifecare Medical Transport business. Without a

corresponding ITE land use code for this land use, the land use was closely observed to

make a very accurate prediction of the total number of trips the land use generates (66

trips). For the other seven sites, the total estimated trips generated, seen in the tables

below, were calculated using either the recommended average rate or the equation found

from following the diagram in Figure 3.1, taken from the ITE Trip Generation

Handbook5. The land use that seemed to produce an overestimation of trips for the site is

the warehousing land use. Both warehousing land uses within this site produced a high

number of estimated trips for that particular land use. This high estimate of trips

58

generated was likely do to the equation rate being too conservative. The total trips

generated from the eight current land uses at the Stoney Ridge Road site are 2,032 trips.

Parcel No Sq Ft Land Use Code ITE Land Use Code Equation/Rates Trips76M1-13 15360 322 Fire Station (Staff) No ITE land use code exists 66 76M1-14 5888 426 Day Care Center (565) Day Care Center 79.26 467

76M1-15 14407 356 Classroom (Elem/2nd Schools) (520) Elementary School Ln(T) = 0.99 LN(X) + 2.59 187

76M1-16 4040 353 Retail Store (812) Building Materials and Lumber Store 45.16 182

76M1-16 30000 406 Storage Warehouse (150) Warehousing T = 3.68(X) + 350.27 461

76M1-17 7064 344 Office Building (715) Single Tenant Office Building 11.57 82

76M1-17 40920 407 Dist. Warehouse (150) Warehousing T = 3.68(X) + 350.27 501

76M1-20 7500 344 Office Building (715) Single Tenant Office Building 11.57 87



4.2.3 Branchlands Boulevard (S-3)

The Branchlands Boulevard site currently consists of three structures (land uses)




found for each parcel within the site. The total estimated trips generated, seen in the



Handbook5. The supermarket land use in this site has a high estimated trip total and the

rate from the ITE Trip Generation Informational Report does not adequately portray this

site. The location of this particular land use is between many other supermarket land uses

that are likely more desirable. This land use also has pedestrian trips from apartment

59

complexes located near the land use, where the use of a vehicle is not necessary;

therefore, the vehicle trip rate for this land use is lower than what is shown in the ITE

Trip Generation Informational Report. The total trips generated from the three current

land uses at the Branchlands Boulevard site are 4,431 trips.

Parcel No Sq Ft Land Use Code ITE Land Use Code Equation/Rates Trips61Z-3-11 36512 353 Retail Store (850) Supermarket 102.24 3733

61Z-3-11B 4946 350 Restaurant (932) High-Turnover (Sit-Down) Restaurant 127.15 629

61Z-3-11C 121 595 Hotel, Limited Service (312) Business Hotel 0.57 69



4.2.4 Premier Circle (S-4)

The Premier Circle site currently consists of five land uses located within the site

that are trip generating. The current land uses in the site are outlined in Table 4.21

below. Using the current land use codes and conducting a site visit, a corresponding ITE

land use code, which most closely represents the land use, was found for each land use

within the site except for one. The current land use that did not have a similar ITE land

use code was a Hobbies and Collectibles shop. Without a corresponding ITE land use

code for this land use, the land use was closely observed to make a very accurate

prediction of the total number of trips the land use generates (20 trips). For the other four

land uses, the total estimated trips generated, seen in the tables below, were calculated


diagram in Figure 3.1, taken from the ITE Trip Generation Handbook5. The estimated

trips generated by the two motel land uses in this site are slightly overestimated by the

rates in the ITE Trip Generation Informational Report. These two land uses have poor

60

accessibility to them and they are outdated, older land uses. The total trips generated

from the five current land uses at the Premier Circle site are 1,323 trips.

Parcel No Sq Ft Land Use Code ITE Land Use Code Equation/Rates Trips61M-6 115 343 Motel (320) Motel Ln(T) = 0.92 LN(X) + 2.11 649 61M-4 46 595 Hotel, Limited Service (320) Motel Ln(T) = 0.97 LN(X) + 2.31 409 61M-3 9000 344 Office Building (710) General Office Building Ln(T) = 0.77 LN(X) + 3.65 209 61M-2 7224 353 Retail Store (890) Furniture Store 5.06 37 61M-2 2450 353 Retail Store No land use code exists 20

1323Table 4.21 Estimated trips generated by current land uses at site (S-4)

4.2.5 Fontaine Research Park (S-5)

The Fontaine Research Park site currently consists of nine structures (land uses)




found for each parcel within this site. The total estimated trips generated, seen in the



Handbook5. For this site, the average rate for the clinic land use is questionable do to the

low number of data points (only 2 studies) that were used in calculating the average rate.

Also, the equation rate for the medical-dental office buildings slightly overestimates the

trips generated by these land uses because they are not as patient based as the rate in the

ITE Trip Generation Informational Report would imply, therefore having a lower rate of

vehicle trips generated by these land uses in the site. The total trips generated from the

nine current land uses at the Fontaine Research Park site are 12,262 trips.

61

Parcel No Sq Ft Land Use Code ITE Land Use Code Equation/Rates Trips76-17A 36928 344 Office Building (710) General Office Building Ln(T) = 0.77 LN(X) + 3.65 619 76-17A 49840 344 Office Building (710) General Office Building Ln(T) = 0.77 LN(X) + 3.65 780 76-17B1 72160 344 Office Building (710) General Office Building Ln(T) = 0.77 LN(X) + 3.65 1038

76-17B2 60000 341 Medical Office (720) Medical-Dental Office Building T = 40.89(X) - 214.97 2238

76-17B3 60000 344 Office Building (710) General Office Building Ln(T) = 0.77 LN(X) + 3.65 900

76-17B6 44607 341 Medical Office (720) Medical-Dental Office Building T = 40.89(X) - 214.97 1609

76-17B7 60380 331 Hospital (630) Clinic 31.45 1899

76-17B8 49141 496 Laboratories (760) Research and Development Center Ln(T) = 0.82 LN(X) + 3.14 563

76-17BW 69204 341 Medical Office (720) Medical-Dental Office Building T = 40.89(X) - 214.97 2615



4.2.6 Hunters Way (S-6)

The Hunters Way site currently consists of nine structures (land uses) located

within the site that are trip generating. The current land uses in the site are outlined in

Table 4.23 below. Using the current land use codes and conducting a site visit, a

corresponding ITE land use code, which most closely represents the land use, was found

for each parcel within this site. The total estimated trips generated, seen in the tables



Handbook5. The total trips generated from the nine current land uses at the Hunters Way

site are 1,590 trips.

62

Parcel No Sq Ft Land Use Code ITE Land Use Code Equation/Rates Trips

78-49B0 2022 344 Office Building (715) Single Tenant Office Building 11.57 23

78-49B1 2250 344 Office Building (715) Single Tenant Office Building 11.57 26

78-49C0 7685 344 Office Building (710) General Office Building Ln(T) = 0.77 LN(X) + 3.65 185

79-4C0 5774 341 Medical Office (720) Medical-Dental Office Building T = 40.89(X) - 214.97 21

79-4D0 44366 407 Dist. Warehouse (150) Warehousing T = 3.68(X) + 350.27 514 79-4L0 5800 386 Mini-Warehouse (151) Mini-Warehouse 2.5 15

79-4M0 9900 525 Mini-Warehouse, Hi Rise

(710) General Office Building Ln(T) = 0.77 LN(X) + 3.65 225

79-4N0 6000 386 Mini-Warehouse (150) Warehousing T = 3.68(X) + 350.27 372

79-4N0 9000 406 Storage Warehouse (710) General Office Building Ln(T) = 0.77 LN(X) + 3.65 209

Total Trips for the Current Land Uses on the Parcel 1590Table 4.23 Estimated trips generated by current land uses at he Hunters Way site (S-6)

4.2.7 Earhart Street (S-7)

The Earhart Street site currently consists of three structures (land uses) located

within the site that are trip generating. The current land uses in the site are outlined in

Table 4.24 below. Using the current land use codes and conducting a site visit, a

corresponding ITE land use code, which most closely represents the land use, was found

for each parcel within the site. The total estimated trips generated, seen in the tables



Handbook5. The total trips generated from the three current land uses at the Earhart

Street site are 421 trips.

Parcel No Sq Ft Land Use Code ITE Land Use Code Equation/Rates Trips

G 4620 356 Classroom (Elem/2nd Schools) (565) Day Care Center 79.26 366

G 4766 353 Retail Store (714) Corporate Headquarters Building Ln(T) = 0.60 LN(X) + 4.32 42

G 5000 406 Storage Warehouse (151) Mini-Warehouse 2.5 13



63

4.2.8 Cedars Court (S-8)

The Premier Circle site currently consists of five land uses located within the site

that are trip generating. The current land uses in the site are outlined in Table 4.25

below. Using the current land use codes and conducting a site visit, a corresponding ITE

land use code, which most closely represents the land use, was found for each land use

within the site except for one. The current land use that did not have a similar ITE land

use code was a Hair Salon & Spa business. Without a corresponding ITE land use code

for this land use, the land use was closely observed to make a very accurate prediction of

the total number of trips the land use generates (44 trips). For the other four land uses,

the total estimated trips generated, seen in the tables below, were calculated using either

the recommended average rate or the equation found from following the diagram in

Figure 3.1, taken from the ITE Trip Generation Handbook5. The total trips generated

from the five current land uses at the Cedars Court site are 1,311 trips.

Parcel No Sq Ft Land Use Code ITE Land Use Code Equation/Rates TripsB 47106 424 Group Care Home (254) Assisted Living 2.66 125 K 1999 223 Commercial No land use code exists 44

G-1 5150 341 Medical Office (720) Medical-Dental Office Building 36.13 186

A-1A, A-1B, A-2, A-3B, PT 1

35388 344 Office Building (710) General Office Building Ln(T) = 0.77 LN(X) + 3.65 600

I, J 50 Condominium (230) Residential Condominium/Townhouse Ln(T) = 0.85 LN(X) + 2.55 356



4.2.9 Summary

When evaluating the trip generation of the current uses, the selection of an ITE

land use code which most adequately represents the land use and the most appropriate

64

rate (average rate or equation) used to determine the trip generation for each parcel was a

very important step in this section. Land use codes for all but three of the land uses in

this study were found in the 7th Edition ITE Trip Generation Informational Report4.

Using the given parcel data (land use, building square feet, etc.) and appropriate trip

generation average rate or equation, the estimated trip generation for the current land uses

was easily attainable. Table 4.26 below shows the total trips estimated for each site given

the current land uses.

Total trips using the Site Name Site Area ITE Tables for the

Current Land Uses Rio East Professional Park 6.493 1480 Stoney Ridge Road 27.590 2032 Branchlands Boulevard 9.074 4431 Premier Circle 6.350 1323 Fontaine Research Park 67.803 12262 Hunters Way 38.659 1590 Earhart Street 1.460 421 Cedars Court 9.162 1311

Table 4.26 Total trips estimated for the Current Land Uses

There were many observations when evaluating the trip generation for the current

land uses by using the information from the ITE Trip Generation Informational Report.

For some of the current land uses analyzed, even though an appropriate ITE land use

code was found to meet the descriptions of the current land use, the current land use in

some cases may not be operating at its full potential. Hence, the estimation of trip

generation for some of the current land uses may be slightly overestimated for a variety

of reasons. Some reasons for trip generation overestimating concerns are:

65

1. Location of the site (possibly along a major corridor)

2. Accessibility characteristics (can the site be easily accessed from all

directions, signal, or right turn-in and right turn-out)

3. Is the site fully developed (do undeveloped or vacant parcels have an

effect on the trip generation for current land uses)

4. The accuracy of the rates selected in the ITE Trip Generation

Informational Report

4.3 FIELD DATA ANALYSIS

Traffic counts were collected for each of the eight sites. The data was collected

for three days during the middle of the week for a typical trip count (Tuesday,

Wednesday, or Thursday) and then an average was taken of the three days. Only one day

of data could be collected at Cedars Court due to a construction project that began shortly

after the first day of data collection. Table 4.27 below shows the actual trip counts for

entering and exiting trips for each site and the day that the data was collected. As seen in

the table, the entering and exiting trip counts were summed to get the total trips per day

for each site. The average trips of the three days was then calculated and determined to

be the actual trip count for a typical weekday for each site.

66

Location Date Entering Exiting Total Average Rio East Professional Park 8/9/2005 972 962 1934 Rio East Professional Park 9/14/2005 891 887 1778 1828 Rio East Professional Park 9/15/2005 891 882 1773 Stoney Ridge Road 8/9/2005 545 542 1087 Stoney Ridge Road 9/20/2005 793 754 1547 1391 Stoney Ridge Road 9/21/2005 804 735 1539 Branchlands Boulevard 8/30/2005 1355 1489 2844 Branchlands Boulevard 9/27/2005 1562 1331 2893 2985 Branchlands Boulevard 9/28/2005 1685 1534 3219 Premier Circle 10/4/2005 343 321 664 Premier Circle 10/5/2004 368 331 699 794 Premier Circle 10/6/2005 536 484 1020 Fontaine Research Park 10/11/2005 2995 3339 6334 Fontaine Research Park 10/12/2005 3065 3302 6367 6212 Fontaine Research Park 10/13/2005 2840 3095 5935 Hunters Way 10/11/2005 789 804 1593 Hunters Way 10/12/2005 779 760 1539 1551 Hunters Way 10/13/2005 758 762 1520 Earhart Street 8/24/2005 161 165 326 Earhart Street 9/14/2005 157 163 320 334 Earhart Street 9/15/2005 173 182 355 Cedars Court 8/24/2005 749 693 1442 1442

Table 4.27 Current traffic field counts from each site

When analyzing the field data on a day-to-day basis for each site, there are a few

factors that come into play, which may have had an effect on the actual traffic counts.

The two main factors that can be seen in the field data above in Table 4.27 are the date

(time of year) in which the data was collected and the second factor being the difference

in land use types within each site (affecting the entering and exiting counts).

When looking at the first factor, late summer to early fall is the time of year in

which the data was collected. Data was collected for three of the sites (Premier Circle,

Fontaine Research Park, and Hunters Way) for 72 consecutive hours (Tuesday-

Thursday). Four of the other sites (Rio East Professional Park, Stoney Ridge Road,

Branchlands Boulevard, and Earhart Street) had counts that were collected for one day in

the month of August and then two more days later in September. The collection of data

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for these four sites may have been affected by the 3-5 week period between data

collection. One possible reason for inconsistency is that children are starting school

around that time period (August-September). In two of the sites where the data varies

(Rio East Professional Park and Stoney Ridge Road), it is very possible that a

discrepancy is due to the time period and the fact that children are beginning school. The

Rio East Professional Park shows that the trip data collected during the one day in August

is much higher than those days later in September. In that site there are land uses such as

Medical and Dental office buildings, which are hypothetically more active when the

school year is approaching, increasing the trips to and from the site. The other site,

Stoney Ridge Road includes land uses such as a day care center and a very small private

school. The data from this site shows a great increase in total trips from the two time

periods (August and September) when data was collected. The two different time periods

for each of these sites could possibly have been affected by the starting of school and

coincidently could have had a minor effect on the average three-day trip count.

When looking at the second factor, the varying land uses in each site had an effect

on the difference of entering and exiting trips. Hypothetically, an analyst would assume

that the entering and exiting trips for a 24-hour count at each site would be similar on a

daily basis; however, due to some of the land uses within each site, this proves to be not

true. Two sites in particular are Branchlands Boulevard and Premier Circle, where both

sites have hotel land uses located within them. Other land uses that may cause

differences in the number of trips entering and exiting are warehouses, supermarkets, and

assisted living housing.

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The three-day average trip counts seen in Table 4.27 for each site will be used as

a basis to validate the estimation procedure. The actual trip counts collected in the field

most accurately portray the current traffic conditions of each site and the total number of

trips entering and exiting the site.

4.4 EVALUATION OF PROCEDURES TO ESTIMATE TRIP GENERATION

FOR GENERALIZED LAND USES

When evaluating the procedure for estimating trip generation for generalized land

uses, the results from the estimated trip generation for current land uses and the actual

traffic counts for each site are going to be used to help validate the estimation procedure

and the procedure’s accuracy. When validating the procedure for estimating trip

generation for generalized land uses, it is important to first compare the total estimated

trips generated by the current land uses and the average traffic field counts. Table 4.28

below shows a comparison between the total estimated trips generated by the current land

uses according to the rates and equations provided in the ITE Trip Generation

Informational Report and the average traffic field counts for each site. The table also

shows the percent difference between the two trip counts.

Average Total trips using the Percent Site Name Site Area Traffic Counts ITE Tables for the Difference

from the Field Current Land Uses Rio East Professional Park 6.493 1828 1480 -19.04 Stoney Ridge Road 27.590 1391 2032 46.08 Branchlands Boulevard 9.074 2985 4431 48.44 Premier Circle 6.350 794 1323 66.62 Fontaine Research Park 67.803 6212 12262 97.39 Hunters Way 38.659 1551 1590 2.51 Earhart Street 1.460 334 421 26.05 Cedars Court 9.162 1442 1311 -9.08

Table 4.28 Total trips estimated for current land uses and actual traffic counts

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As seen in Table 4.28, four of the sites have percent differences of 45% or greater

when looking at the two trip counts. The total estimated trips for the current land uses in

these four sites seem to be greatly overestimated, compared to the number of trips the

land uses actually produce. This can be for a variety of reasons such as the location of

the site (urban or suburban), the land uses within the site (some less desirable), and the

access characteristics of the site. Not only is the overestimation of trips for these sites

possibly a result of the varied characteristics of the land uses themselves, but also it is

possible that the rates used in calculating the estimation of trips generated for the current

land uses from the ITE Trip Generation Informational Report do not adequately portray

all of the current land uses within the site. Consequently, overestimating the trips

generated by the current land uses may have occurred because a rate from an inadequate

land use code was used.

When comparing estimation of trip generation for generalized land uses with the

estimated trips for the current land uses and the actual traffic counts for each site as seen

in Table 4.29 below, it is evident that the total trips from the estimation procedure for

generalized land uses and the total trips estimated from the current land uses greatly vary

for each site. As seen in Table 4.29, no pattern can be established between the two sets

of trip generation data. This variance between the two estimated trip counts is mostly a

result of the difference in the selected potential land uses used in the procedure for

estimating trip generation for generalized land uses and the land uses that currently exist

along with the corresponding trip generation rate used for each land use.

As seen in Table 4.29 below, the Stoney Ridge Road site, the Branchlands

Boulevard site, and the Earhart Street site are the only sites in this study where the

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estimated trips generated for generalized land uses in both scenarios is less than the

estimated trips generated by the current land uses (i.e. applying the ITE Trip Generation

rates to the current land uses). For all of the other sites, the trips generated by the

estimation procedure for generalized land uses was much greater than those trips

generated by the current land uses. This shows that the selected potential land uses to be

placed on the site in the procedure to estimate trip generation for generalized land uses

has a great affect on the total trips to be estimated for the site.

Estimation Procedure Total trips using the Average Site Name Total Trips Total Trips ITE Tables for the Traffic Counts

Scenario 1 Scenario 2 Current Land Uses From the Field Rio East Professional Park 1886 2438 1480 1828 Stoney Ridge Road 1662 1493 2032 1391 Branchlands Boulevard 3059 3426 4431 2985 Premier Circle 2253 2166 1323 794 Fontaine Research Park 13934 11860 12262 6212 Hunters Way 3838 3211 1590 1551 Earhart Street 336 279 421 334 Cedars Court 1491 1858 1311 1442

Table 4.29 Total trip count comparison for all of the sites

Another difference between the estimated trip generation for generalized land

uses and the land uses that currently exist is the FAR value. When comparing the

average FAR values of the different zoning classifications, which were used in

calculating the density and area in the estimating trip generation Equation 3.3 and the

FAR values of the current site under the site’s existing conditions, the FAR values are

significantly different. This difference in FAR values shows that the quantity of

development (density) calculated in the procedure for estimating trip generation for

generalized land uses is overestimating the development for the chosen sites. As seen in

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the Table 4.30 below, the average FAR value for all of the sites is greater than the FAR

value of the current land uses for each site. In six of the eight sites, the average FAR

value used in the procedure for estimating trip generation for generalized land uses is

34% or greater. Using the average FAR value to calculate the density and area in the

procedure for estimating trip generation for generalized land uses may have caused the

estimated trips generated to be overestimated because the density of each site is

overestimated when compared to the density of the current land uses that exist at each

site. Using the average FAR in terms of “zoning” in this procedure is not a very valid

method in determining the most accurate portrayal of local density. Using the average

FAR in terms of zoning allows for a wide range of varying potential land uses found

within the zoning ordinance that will have the same FAR for each potential land use

selected. An example of this would be applying the same average FAR value to a general

office building and a retail store because they have the same zoning, even though in

actuality, a general office building typically has a higher FAR value than a retail store.

Site Name Zoning Avg. FAR value FAR value of Existing % County/City Land Uses Difference

Rio East Professional Park PDMC 0.247 0.174 41.94 Stoney Ridge Road PUD 0.140 0.104 34.42 Branchlands Boulevard PUD 0.140 0.082 70.49 Premier Circle C1 0.216 0.204 5.80 Fontaine Research Park CO 0.172 0.170 1.10 Hunters Way LI 0.172 0.055 212.21 Earhart Street MUC 0.306 0.226 35.53 Cedars Court MUC 0.306 0.225 36.14

Table 4.30 Comparison between the avg. FAR and the FAR of the current land uses

Another cause in the variance between the total estimated trips for generalized

land uses and the total trips estimated for the current land uses and the actual trip counts

72

from the field is the total size (acreage) of the site. As the site size increases, there is a

greater chance of similar (high or low trip generating) land uses to be found on the site.

The bigger the site, the wider the range of possible estimated trips generated and the less

accurate the estimation procedure for calculation purposes.

In evaluating the procedure for estimating trip generation for generalized land

uses, a number of variables were found, which had an effect on the total estimated trips

generated for each site. These variables include the zoning, the selected potential land

uses, the average FAR values, the total size of the site, and the location of the site.

Another variable that should be considered but is hard to quantify, is the time between the

start of the procedure and the actual finished development. As time passes, the local

characteristics (data) used in the estimation procedure may change. The accuracy of this

procedure for estimating trip generation for generalized land uses is documented in the

conclusion of this report.

73

Chapter 5: Guidelines for State and Local Planners

Based on the information obtained in this study, the following guidelines can be

applied by state and local planners to help them use the procedure for estimating trip

generation for generalized land uses. Steps in this procedure include:

1. Determine the potential mix of land uses in the selected site

2. Estimate the appropriate development quantity

3. Estimate trips generated by the total site

4. Test a range of possible scenarios

5.1 DETERMINE POTENTIAL MIX OF LAND USES

A fitting trip generation estimate for a site should reflect, to the extent possible,

the specific land uses within the known zoning classification of the local zoning

ordinance. Potential land uses for a site are best determined by knowing which specific

ITE land use codes or classifications found in the ITE Trip Generation Informational

Report are acceptable given a particular zoning classification. It is very important for the

planner to first read the local zoning ordinance that applies to the chosen site of study. A

list of all potential land uses found in the ITE Trip Generation Information Report for the

site that are acceptable land uses according to the expected zoning classification should

then be developed.

Once this list of potential land uses is complete, it is necessary for the analyst to

review this list with other suitable local public officials. Specific land uses for the site

should then be chosen based on the current surrounding land uses in the area. It is also

important for the analyst, when selecting specific land uses for the site, to observe

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existing land uses within recently developed areas under the same zoning classification,

preferably with similar site size and access characteristics.

5.2 ESTIMATE THE APPROPRIATE DEVELOPMENT QUANTITY

When analysts are estimating typical development densities, GSF/acre, DU/acre,

or a similar ratio should be obtained for the chosen land uses in the site. Even though

typical development densities can be found in national publications, it is very important

to use local densities found in the area where the site is located. Typical development

densities may vary in different parts of a region; therefore, it is critical to be as locally

accurate as possible in terms of density. Real estate databases used by different

appraisers such as the Computer Assisted Mass Appraisal (CAMA) can help analysts to

find the local densities of an area because this database includes information such as

building square footage, land area (acreage), zoning classification, etc. The local typical

densities can be estimated from the average floor-area-ratio (FAR) value for all land uses

with a similar zoning classification (city or county). An example of this is a site having a

zoning classification of Planned Development Mixed Commercial (PDMC) and the

coinciding average FAR value for every site in that particular county with similar zoning

(PDMC) is 0.247. In order to get a more specific FAR value for the site, if needed, the

analyst may use the CAMA database to search for sites that are similar in site size, access

characteristics, location, etc. Analysts may also use the CAMA database to find local

average FAR values in terms of “land use” for the potential land uses selected to be place

on the site.

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The density can then be calculated using Equation 5.1 below, where the floor-

area-ratio (FAR) is 0.247, the 43,560 square feet is the conversion for one square acre,

and the Stories is the number of stories in the building. The equation below will then

solve for density as ksf/acre for the land use.

xStoriesFARxD ⎟⎠⎞

⎜⎝⎛=

100043560

(5.1)

Another step involved with estimating an appropriate development quantity is

calculating the appropriate area needed for each land use within the site. The area (A) for

each land use is found as acreage and can also be calculated using an equation. For each

selected land use within the site, the analyst must estimate an appropriate square footage

of the land use (building/structure) to be placed on the site. Using an average FAR value

that more adequately reflects the land use will produce more accurate trip generation

results. Using the appropriate average FAR value, the analyst can use the same FAR

value to determine the acreage needed for a given land use using Equation 5.2 below.

The equation includes the estimated square footage of the structure of the land use, the

average FAR value, and the number of stories in the structure.

StoriesFARSFA /43560//= (5.2)

For example, if an estimated square footage of a structure located on a land use is

10,000 SF, the average FAR value for the particular zoning classification is 0.247, and

the building structure is only one story, then the estimated area needed for this land use is

0.929 acres.

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5.3 ESTIMATE TRIPS GENERATED BY THE TOTAL SITE

The estimation of trip generation relies heavily on the rates that are chosen

following the recommended procedure (refer to Figure 3.2) for the estimation of trip

generation equation (Equation 5.3). For most all studies, either the equation or the

average rate should be used as a trip generation rate even though the figure shows that the

analyst may need to collect local data for a particular parcel, which may not be possible

for the analyst.

The trip generation rates should be developed in the most disaggregate level

possible, such as gross square footage (GSF) instead of acres. Given that a majority of

the studies in the ITE Trip Generation Informational Report are done with the gross

square footage (GSF) as the independent variable, this is a good development unit to get

the best results with a wide range of land uses. The analyst should be cautioned when

selecting the most appropriate rate to be used and should be observant to the number of

studies conducted, R2 value, and standard deviation of the potential land use to ensure a

more accurate trip generation estimate.

The trip generation estimate in terms of total trip ends (T) per parcel or land use in

a site is obtained by multiplying the trip generation rate (R) times the weighted density

(D) times the area (A) as seen in Equation 5.3 below.

( )RxDxAT = (5.3)

The product of density (D) and area (A) in the above equation is simply the

number of development units that match the independent variable for the assumed trip

generation rate, based either on the weighted average rate or the regression equation.

77

The trip generation estimate (T) for the total site can then be obtained by

summing the product of the rate, density, and acres of individual land uses using

Equation 5.4 below, where i corresponds to the individual land uses within the site.

( )∑=i iii xAxDRT (5.4)

Using the above equation, the total estimated trips can be calculated for the total

site.

5.4 TEST A RANGE OF POSSIBLE SCENARIOS

During the final step of the procedure to estimate trip generation for generalized

land uses, it is important for the analyst to possibly test a range of scenarios to include

many of the development possibilities for the study. Differing scenarios consist of

varying land use mixes and varying development quantities to be used in estimating trip

generation for the site. If there is a strong level of uncertainty regarding the possible land

use mix and the development density for the site, it is wise for the planner to test a wider

range of scenarios with varying land use mixes and densities to get a better understanding

of the range of possible trips that may be generated by the site. From the range of

scenarios the planner can then evaluate the extent of possible needed roadway

improvements to account for increased traffic from the development, such as changing a

two-lane roadway to a four-lane roadway or implementing a signal.

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5.5 SUMMARY

This procedure for estimating trip generation for generalized land uses is an

improved procedure to use for general planning and land use applications in order to help

planners understand “quickly” the possible trip generation impact of a particular site

without doing a detailed traffic impact analysis. The procedure used in this methodology

differs from that found in Chapter 6 of the ITE Trip Generation Handbook by using the

CAMA databases to help in determining local densities. The usefulness of the CAMA

database to find and determine local FAR values is an enormous help to the analyst in

following this procedure and improving the accuracy of the estimation. The results from

using this procedure produce very general estimates and are not appropriate for use in

more detailed traffic impact analysis studies, which are necessary during later stages of

development.

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Chapter 6: Conclusions

Based on the results found in this study, several conclusions can be made from

following the procedure for estimating trip generation for generalized land uses. The

methodology used in this project closely follows the methodology described in Chapter 6

of the ITE Trip Generation Handbook for “Estimating Trip Generation for Generalized

Land Uses.” The most significant improvement to the methodology used in the ITE Trip

Generation Handbook is using the CAMA database in determining average FAR values

to help in calculating development quantities based on local densities. In the procedure

described in Chapter 6, there is no clear way of identifying appropriate development

quantities, which accurately portray the typical local development densities. The use of

the CAMA database to find FAR values was an attempt to improve and simplify the

procedure for estimating trip generation for generalized land uses.

The accuracy of this procedure for estimating trip generation for generalized land

uses greatly depends on the accuracy of each and every variable (rate, density, and area)

within the trip generation Equation 5.3. Below are a number of factors, which have an

effect on the accuracy of the variables used in the estimation equation. By improving the

accuracy of each variable, the accuracy of the entire process for estimating trip generation

for generalized land uses will be improved. The following points are formed from the

results found in this project and discuss the issues involved with each variable while

making suggestions to improve the accuracy of each variable.

1. Issue: The selected potential land uses to be used in estimating trip generation for

generalized land uses in any scenario may not be what is actually developed and built

at the site, hence altering the number of trips generated.

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Solution: This procedure for estimating trip generation for generalized land uses is a

trip generation “guessing” procedure for general planning. Selecting and applying

land uses to a particular site does not mean that those land uses are actually going to

be built and developed on the site; therefore, the selected land uses are possibilities.

Selecting the best possible potential land uses to be developed on the site, from the

permissible land uses found in the zoning ordinance, can best be determined by

discussing the land use possibilities with local planners, developers, political leaders,

and the land owner. Local planners will be able to best determine the potential land

uses by directly following the development vision of the community. Although this

procedure for estimating trip generation for generalized land uses is not 100%

accurate, it is better than having no information to help in the early planning stages of

a project.

2. Issue: Using the average FAR values found from the CAMA database in terms of

each zoning classification for each site was the approach used when this project

began; however, it is not an accurate way of portraying the local density. Applying

the same average FAR value in terms of zoning to a wide range of various land uses,

does not accurately portray each land use because it assumes that all of the land uses

(whether a warehouse, a general office building, a retail store, a hotel, a restaurant,

etc.) will have the same FAR.

Solution: Using the CAMA database is a very useful tool in determining local

average FAR values. It is extremely important to determine the FAR values as

accurately as possible, where the average FAR value adequately portrays the land use.

One way to improve upon the accuracy of the average FAR value is to use the CAMA

81

database to determine average FAR values that reflect each individual land use. For

example, instead of using the average FAR value from a zoning code, such as PDMC

as seen in this project, the analyst should find and use an average FAR value that

reflects a warehouse or office building land use. Using an average FAR value that

more adequately reflects the land use will produce more accurate trip generation

results.

3. Issue: The trip generation rates found in the ITE Trip Generation Informational

Report used in the calculation may be inaccurate for a variety of reasons such as a

land use having a low number of studies, low R2 value, or good standard deviation.

Land uses that are used that represent poor statistical information will provide rates

that are likely to be inaccurate, leaving much room for variation in the trip generation

estimate.

Solution: Select potential land uses from the ITE Trip Generation Informational

Report that have very good statistical information so that the trip generation rate used

will be valid. When selecting potential land uses, the analyst should select land uses

that have many data points and high R2 values. Following the recommended

procedure for selecting between trip generation average rates and equations is an

excellent method to use; however, when the analyst observes the potential land use in

the ITE Trip Generation Informational Report, if the land use has a very low number

of studies or low R2 value (if any R2 value), that land use should not be used in the

trip generation estimation because the statistical information for that land use does not

support and validate the accuracy of the trip generation rate of the land use.

82

In the beginning and throughout this project, the purpose of the methodology was

to validate the procedure for estimating trip generation for generalized land uses. In the

process, this procedure was found to be difficult to validate because each of the selected

sites included in the study had many differences. The sites studied varied by the zoning

of the site, land uses on the site, the total size (acres) of the site, the location of the site

(urban or suburban area), the proximity to similar sized corridors, and the accessibility

characteristics. All of these variations led to results that could not conclusively validate

the procedure for estimating trip generation for generalized land uses. The only real way

to validate an estimation procedure such as this is to test it with sites that are extremely

similar, and such sites are difficult, if not impossible to find. Finding sites that are

characteristically 100% similar in zoning, site size, current land uses, accessibility,

proximity to similar sized highways, and location (urban or suburban area), however will

greatly reduce the variations between testing sites, thus validating this procedure for

estimating trip generation for generalized land uses.

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Chapter 7: Recommendations for Further Study

Based on the results found in this study, there are several areas of research where

further investigation is needed:

1. Test Chapter 6 in the ITE Trip Generation Handbook by developing more scenarios

to be applied to each site. Having more scenarios will improve the average total trip

count in the procedure for estimating trip generation for generalized land uses.

2. Test Chapter 6 in the ITE Trip Generation Handbook further by studying sites that are

more closely related characteristically. Using sites that consist of similar land uses,

site size, accessibility from other major roadways, and location (urban or suburban)

will help to keep some consistency between the study sites. Sites should also be

selected that are fully developed and consist of relatively newer land uses. Selecting

sites to study that are more comparable to one another will help to ensure that the

total estimated trips generated by the current land uses will be more closely related

because similar trip generation rates will be used.

3. Test Chapter 6 in the ITE Trip Generation Handbook further by selecting sites to

study that consist of more than one or two entrance and exit points. These entrance

and exit points will improve the accessibility to the site, thus possibly increasing the

actual traffic field counts for the current uses.

4. Analyze regional, state, and national trends in floor-area-ratios (FAR) and determine

if parcels with similar zoning and location (e.g. primary highway) are similar.

5. Improve the accuracy of the average FAR value used in calculating area and density

for study sites in the context of zoning categories and average FAR values found from

84

each by using the average FAR values of the parcels found in similar surroundings as

the study site (e.g. on a primary highway) and not the entire zoning category

throughout the county or city. Land uses with similar zoning categories across a

region, may have very different FAR values; therefore, using the FAR values of the

surrounding parcels of the study area, even if the zoning classification varies, will

most adequately represent the local densities of the study area.

6. Attempt to refine the appropriate ITE land use code selection. Find a way to link the

information in the CAMA database (such as zoning, land use, square footage,

acreage, etc.) to specific ITE land use codes supplied in the ITE Trip Generation

Informational Report.

7. Simplify the ITE recommended procedure for selecting between trip generation

average rates and equations to eliminate the suggestion of collecting local data and

choosing the line at the cluster. Improving the recommended procedure may include

a suggestion for the analyst to select a different potential land use because there is

insufficient statistical information (low number of studies, low R2 value, or standard

deviation) in the selected land use. If the analyst selects a land use with inadequate

statistical information, the recommended procedure should direct the analyst to

choose a different potential land use. More reported studies in the ITE Trip

Generation Informational Report may be needed.

85

References 1. The Scan Team. Land Use and Transportation Coordination: Lessons Learned

from Domestic Scan Tour Report. 2003. http://www.planning.dot.gov/Documents/ DomesticScan /domscan603.htm.

2. Virginia Code. Ann. §15.2-2200, available at http://leg1.state.va.us/cgi-bin/legp504

.exe?000+co h+15.2-2200+401359. 3. Albemarle County Code. Chapter 18 Zoning. 2006. http://www.albemarle.org/upl

oad/images/forms_center/departments/county_attorney/forms/Albemarle_County_Code_Ch18_Zoning01_Authority_Purpose.pdf.

4. Trip Generation. Seventh Edition. Volume 2 and 3. Washington, D.C.: Institute

of Transportation Engineers. 2003. 5. Trip Generation Handbook: An ITE Recommended Practice. Washington, D.C.:

Institute of Transportation Engineers. 2001. 6. Martin, William A. and McGuckin, Nancy A., “Travel Estimation Techniques for

Urban Planning.” NCHRP Report 365, Transportation Research Board, National Research Council, Washington, D.C. 1998.

7. Trip Generation. Fifth Edition. Washington, D.C.: Institute of Transportation

Engineers. 1991. 8. Trip Generation. Seventh Edition. User’s Guide, Volume 1. Washington, D.C.:

Institute of Transportation Engineers. 2003. 9. Shoup, Donald, “Roughly Right of Precisely Wrong.” Access: Number 20,

University of California Transportation Center. 2002. http://www.uctc.net/access/ access20.pdf.

10. Bochner, Brian. Email. 27 March 2006.

86

APPENDIX A

Tax Maps

87

Rio East Professional Park

The parcels listed below include all of the parcels used for data collection within this site. 124C – Alltel – Office Building 124B1 – Geraty Investments LLC – Office Building 124B2 – Rio East LLC C/O Workman – Office Building 124B3 – RGMJ LLC – Medical Office Building 124B4 – Medical Office Building 124B5 – Don Johnsbert Properties LLC – Medical Office Building 124B6 – Danel Enterprises L C – Medical Office Building 124B7 – Sugar Mountain LLC – Medical Office Building 124B8 – Refined Redneck LLC – Medical Office Building 124A1 – MD Development – Medical Office Building The parcels which are currently undeveloped (vacant) within the site that was not used in this study include the following: 61-124A – Rio East Land Trust – Vacant Commercial

88

Stoney Ridge Road

The parcels listed below include all of the parcels used for data collection within this site. 76M1-13 – Executive Properties LLC – Fire Station 76M1-14 – Day Care Center 76M1-15 – Peabody School – Classroom (Elem/2nd Schools) 76M1-16 – Stoney Ridge Road LLC – Retail Store, Storage Warehouse 76M1-17 – FedEx – Office Building, Dist Warehouse 76M1-20 – Paper Company – Office Building The parcels which are currently undeveloped (vacant) within the site that were not used in this study include the following: 76M1-11– Vacant Industrial 76M1-12 – Vacant Industrial

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Branchlands Boulevard

The parcels listed below include all of the parcels used for data collection within this site. 61Z-3-11 – Foodlion – Retail Store 61Z-3-11B – Applebee’s – Restaurant 61Z-3-11C – Fairfield Inn – Hotel, Limited

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Premier Circle

The parcels listed below include all of the parcels used for data collection within this site. 61M-2 – Retail Store 61M-3 – Offices Building 61M-4 – Royal Inn Motel – Hotel, Limited 61M-6 – Red Carpet Inn – Motel

91

Fontaine Research Park

The parcels listed below include all of the parcels used for data collection within this site. 76-17A – Division of Natural Resources & State Police 76-17B1 and 76-17BX are the same parcel– Office Building 76-17B2 – Medical Office Building 76-17B3 – Office Building 76-17B6 – Medical Office Building 76-17B7 – Hospital 76-17B8 – Laboratories 76-17BW – Medical Office Building

The parcels which are currently undeveloped (vacant) within the site that were not used in this study include the following: 76-17B – Vacant Office Lot 76-17B4 – Vacant Residential Lot 76-17B5 – Vacant Residential Lot 76-18 – Vacant Residential Lot 76-19 – Vacant Residential Lot

92

Hunters Way

The parcels listed below include all of the parcels used for data collection within this site. 78-49B0 – VA School Board Association 78-49B1 – Craft Technology 78-49C0 – Office Building 79-4C0 – Medical Office Building 79-4D0 – UPS Warehouse 79-4L0 – Mini-warehouse 79-4M0 – Office Building 79-4N0 – Mini-warehouse and Office Building The parcels which are currently undeveloped (vacant) within the site that were not used in this study include the following: 78-49A0 and 78-49A1 and 78-49A2 – Culver Technology Group 78-49D0 – Vacant Land 78-49E0 – Vacant Land 78-49F0 – Vacant Land 78-49G0 and 79-4B0 – Vacant Office Building and Warehouse, combined parcels 79-4L1 79-4P0

93

Earhart Street

The parcels listed below include all of the parcels used for data collection within this site. G – Kinder-Care Learning Center – Classroom (Elem/2nd Schools) G – Blue Ridge Mountain Sports – Retail Store, Storage Warehouse

94

Cedar Court Road

The parcels listed below include all of the parcels used for data collection within this site. B – Group Care Home K – Commercial G-1 – Medical Office Building A-1A, A-1B, A-2, A-3B, PT 1 – Office Building I, J – Cedar Court Condominiums (50 of them) – Condominiums The parcels which are currently undeveloped (vacant) within the site that were not used in this study include the following: H-1 – Office Building