Chapter 4 1 Chapter 4. Modeling Transportation Demand and Supply 1.List the four steps of transportation demand analysis 2.List the four steps of travel.

Chapter 4Chapter 4 11

Chapter 4. Modeling Transportation Chapter 4. Modeling Transportation Demand and SupplyDemand and Supply

1.1. List the four steps of transportation demand analysisList the four steps of transportation demand analysis2.2. List the four steps of travel demand forecasting modeling List the four steps of travel demand forecasting modeling

processprocess3.3. Identify, quantify, and discuss the relationship between Identify, quantify, and discuss the relationship between

land use and transportation activityland use and transportation activity4.4. Calculate estimates of the number of trips “generated” by a Calculate estimates of the number of trips “generated” by a

particular land useparticular land use5.5. Explain the purpose of Traffic Analysis Zone (TAZs)Explain the purpose of Traffic Analysis Zone (TAZs)6.6. Explain two-way relationship between land use and travelExplain two-way relationship between land use and travel

We cover only 4.1 in this class. By the end of this section the student will be able to:

Topics of Chapter 4 and Chapter 5 will be covered in CEEn 565 Urban Transportation Planning taught by Dr. Schultz. (It will be offered in the fall semester every year.) If you are planning to take CEEn 565 keep this textbook because Dr. Schultz covers the entire materials of Chapters 4 and 5 of this textbook as part of his course.

Mythaca’s Mythaca’s congestion congestion

problemproblem(SR361)(SR361)

22Chapter 4Chapter 4

33Chapter 4Chapter 4

Mythaca’s Mythaca’s congestion congestion

problemproblem(SR361): (SR361):

one one solution solution (bypass) (bypass)

and and change in change in

traffictraffic

44Chapter 4Chapter 4

4.1.1 Anticipating future network needs

Transportation planning is a process that involves:

the analysis of current travel patterns,

the forecasting of future travel patterns (Transportation Demand Analysis),

the proposal of transportation infrastructure and services, and

the evaluation of proposed alternative projects to be considered by decision makers for implementation

The result is a plan – A set of improvements to be

considered by decision makers.

Basic concepts of travel demand modeling:

• Travel demand is a derived demand

• Travel patterns are influenced by land use

• Individuals’ decision making habits influence travel demand

http://www.envisionutah.org

http://www.mountainland.org/

55Chapter 4Chapter 4

Data collection Data collection (population, land (population, land use, etc.)use, etc.)

Economic activity (employment, sales volume, income, Economic activity (employment, sales volume, income, etc.), land use (type, intensity), travel characteristics (trip etc.), land use (type, intensity), travel characteristics (trip and traveler profile), and transportation facilities (capacity, and traveler profile), and transportation facilities (capacity, travel speed, etc.), population and demography, Origin-travel speed, etc.), population and demography, Origin-destination trip data.destination trip data.

Analysis of existing Analysis of existing conditions and conditions and calibrationcalibration

Analyze the data collected in the data collection stage. You Analyze the data collected in the data collection stage. You may build mathematical models to describe the existing may build mathematical models to describe the existing conditions and then use the relationships you have found conditions and then use the relationships you have found in the existing parameters to forecast future values.in the existing parameters to forecast future values.

Forecast of future Forecast of future travel demandtravel demand

4-step 4-step transportation demand forecasting modeling transportation demand forecasting modeling processprocess

Analysis of the Analysis of the resultsresults

Analyze what you get from the 4-step demand forecasting Analyze what you get from the 4-step demand forecasting processprocess

General 4 steps of transportation demand analysis

66Chapter 4Chapter 4

4-step transportation 4-step transportation demand forecasting demand forecasting modeling processmodeling process

Preparation: population and economic analysis and Preparation: population and economic analysis and land use analysisland use analysis

Trip generationTrip generation Determines how many trips each activity (center) Determines how many trips each activity (center) (residential area, commercial area, etc) will produce or (residential area, commercial area, etc) will produce or attractattract

Trip Trip distributiondistribution

Determines the origin or destination of trips that are Determines the origin or destination of trips that are generated at a given activitygenerated at a given activity

Modal splitModal split Determines which mode of transportation will be used Determines which mode of transportation will be used to make the tripto make the trip

Traffic Traffic assignmentassignment

Determines which route on the transportation network Determines which route on the transportation network will be used when making the tripwill be used when making the trip

77Chapter 4Chapter 4

Travel demand Travel demand forecasting forecasting

modeling process modeling process (4-step model)(4-step model)

1. Should I make a trip?

2. What should be my destination?

3. What mode of transportation should I use?

4. What route or path should I take?

p.187 Think About It: Think back to the last four or five trips you made. Did you ask yourself any or all of the four questions above? If so, in what order did you consider the questions.

88Chapter 4Chapter 4

4.1.2 Land use and tripmaking

Finding how many trips are generated from a zone is the first step of urban transportation demand modeling. At a macro level, it is a region wide demand forecasting and at a micro level the public agency wants to know how many trips a development in a land can produce – like how many trips a planned Walmart might produce.

Tripmakers

Land useTransportation facilities

MAG’s 2040 Transportation PlanDemand Forecasting

99Chapter 4Chapter 4

Estimating the number of trips generated:

CEEn 565 deals with various methods to do this step, but in this lecture, we use charts found in the ITE Trip Generation Handbook to show you how to get quickly ballpark estimates – and of course a few pitfalls...

(Walk through Example 4.1.)

1010Chapter 4Chapter 4

Analysis zones for transportation study (TAZ), Analysis zones for transportation study (TAZ), p.194-196p.194-196First, we need to divide

the study area into smaller zones of (hopefully) uniform land use

Dense area, in terms of population and businesses, has more zones. Zones usually get larger in less dense areas.

More reasonable to use TAZ thana site-by-site analysis when regional planning is done.

Standard trip generation methods:• site-based• zone-based• household-based

1111Chapter 4Chapter 4

Link-node map for highway systemLink-node map for highway system

Link-node maps are the starting point for the 4-step transportation demand forecasting process

1212Chapter 4Chapter 4

Graphical way of understanding the 4-step Graphical way of understanding the 4-step demand forecasting processdemand forecasting process

1000 trips generated in zone 46: residential area zone

1000 trips attracted to zone 29: employment center

200 trips from zone 46 to zone 29

Auto total: 95%(190 trips)

Public transit: 5%(10 trips)

70% this route (140 trips)

25% this route (50 trips)