07 04 23 Pavement Data Collection Services Generic Spec v1.0
Nov 03, 2015
Generic Terms of Reference
Generic Terms of Reference
Pavement Data Collection Services
Version 1.0 April 23, 2007
East Asia Pacific Transport Unit
The World Bank
Washington, D.C.The World Bank
East Asia Transport Unit
1818 H Street NW
Washington, D.C. 20433, U.S.A.
Tel: (202) 458-1876
Fax: (202) 522-3573
Email: [email protected]: www.worldbank.orgA publication of the World Bank East-Asia Transport Unit sponsored by the Transport and Rural Infrastructure Services Partnership (TRISP). The TRISP-DFID/World Bank Partnership has been established for learning and sharing knowledge.This specification is a product of the staff of the World Bank assisted by independent consultants. The findings, interpretations, and conclusions expressed herein do not necessarily reflect the views of the Board of Executive Directors of the World Bank or the governments they represent.
The World Bank does not guarantee the accuracy of the data included in this work. The boundaries, colors, denominations, and other information shown on any map in this work do not imply any judgment on the part of the World Bank concerning the legal status of any territory or the endorsement or acceptance of such boundaries.
Quality Assurance Statement
Report Name:Generic Terms of Reference for Pavement Data Collection ServicesPrepared by:R. Mallela
Reviewed by:
T.Henning, D.Brown, T.Thomsen
Project Manager:
C.R. Bennett
[email protected] for issue by:C.R. Bennett
23 April, 2007
Revision Schedule
Rev. NoDateDescriptionPrepared byReviewed byApproved by
Generic Terms of Reference for Pavement Data Collection Services
This document presents a generic Terms of Reference (TOR) to be used for the procurement of road and pavement data collection services. It details the requirements for establishing the location referencing and measuring pavement roughness, rutting, texture, skid resistance, road geometry and Right of Way (ROW) video.
It is intended that data collected will be used for pavement management and should meet or exceed the specific requirements as detailed in this document based on the Information Quality Level concept.
This generic TOR can be used by any roads agency as a basis for developing a specific data collection TOR that meet the particular network or survey requirements. The user may select equipment with all facilities or only those deemed necessary for the particular network or agency.
This generic TOR contains the minimum specifications required to achieve the level of accuracy and repeatability for the user to have the necessary confidence in the data collected to facilitate the on going analysis for network maintenance and upgrading.
Accompanying notes provide some additional background information, discussion, and typical solutions that may assist the Client in preparation of a detailed TOR for procurement. The Client may decide to include some of these notes in an actual TOR. However it is generally considered better to let the Consultant or vendor elaborate on their understanding and approach in the proposal/bid, and to suggest alternative solutions, rather than to be too prescriptive in the Specification on the actual solution, approach or methodology.
This generic TOR does not include details of the Road Management System (RMS) or end use for the collected data and therefore the client will need to be aware of data format, data reporting intervals, and requirements for data that a particular RMS may require when specifying a particular data item.
Much of the background research required to determine what measurements a particular highway agency should be considering are detailed in the report Data Collection Technologies for Road Management which describes the different types of available technologies and how to select the most appropriate technology for a given situation.
Notes on the Format
1.1 Section / Clause HeadingYes
Text in boxes with blue shading is intended for client staff preparing the TOR. It includes background explanation on the purpose of the clause, and additional discussion as appropriate.
Text in gray boxes indicates actual text that may be included in a TOR.
White boxes are spaces for Client notes while planning the TOR.Table of Contents
31OBJECTIVES
31.1Objectives of the Client
31.2Procurement Process
52COMMON SPECIFICATIONS
52.1Terminology
62.2Roles of the Parties to the Contract
62.3Term of the Contract
72.4Data Requirements
92.5Data to be Collected
112.6Survey Network
132.7Special Instructions
132.8Survey Header Data
142.9Survey Equipment
142.10Contractor Skills
152.11Survey Procedure
162.12Location Referencing System
172.13Equipment to be Provided by Client
172.14Equipment to be Provided by Contractor
182.15Data Format
193DATA COLLECTION SPECIFICATIONS
193.1Location Referencing
213.2GPS Centerline Coordinates
233.3Road Inventory
263.4Geometry
273.5Condition
323.6Pavement Structure
343.7Traffic Counting
353.8Right of Way Video
353.9Digital Photographs
353.10Cross Drainage Structures
374CALIBRATION AND VALIDATION
374.1Calibration Methodology
384.2Validation Methodology
404.3Roughness
404.4Rutting
414.5Texture
424.6Skid Resistance
434.7Road Geometry GPS
444.8Right of Way Video
444.9Others
454.10100 km Field Validation
454.11Acceptance for Survey Certificate
454.12Contract Termination
475QUALITY CONTROL AND ASSURANCE
475.1Quality Control and Assurance - General
475.2Quality Management Plan
485.3Data Display
495.4Data Backup
495.5On-going Validation
516TRAFFIC MANAGEMENT AND SAFETY
516.1Traffic Management Plan
527DATA PROCESSING AND STORAGE
527.1Data Format
527.2Provision of Data
537.3Supplemental Software
537.4Data Review and Acceptance
558MONITORING AND REPORTING
558.1Initial Meeting
558.2Inception Report
568.3Quality Management Plan
568.4Calibration and Validation Manual
568.5Data Management Manual
578.6Survey Procedures Manual
578.7Progress Reports
588.8Final Report
598.9Progress Review Meetings
609KEY DELIVERABLES
609.1Deliverables
609.2Format
619.3Intellectual Property
6210SCHEDULE AND RESOURCES
6210.1Project Schedule
6210.2Data Collection Contractors Personnel
6310.3Services and Facilities Provided by the Client
6511BASIS OF PAYMENT
6511.1Basis of Payment
6511.2Payment
1 OBJECTIVES
1.1 Objectives of the ClientYes
Common objectives of clients obtaining pavement and road condition data are listed below. To enforce appropriate and industry standard data collection procedures.
To ensure appropriate calibration, validation and quality procedures are followed.To establish a road and pavement condition database to use with Road Management Systems.To establish industry standard systems and processes associated with pavement inventory and condition data.
To monitor network condition status and perceived benefits from the maintenance practices.
The data collection services provide a means for the collection of accurate and repeatable pavement condition data which will assist the Client in defining the true condition of the road network. The data collected will be used to: Provide network condition data to facilitate year on year comparisons and to define and track changes in the network condition.
1.2 Procurement ProcessYes
This TOR calls for the procurement only to be completed after the data has been validated (see Section 4). Validation is essential as it ensures that the data collected fully conforms to the clients specification. The validation also confirms that the equipment used can measure the required parameters on the network and under the conditions where it is intended.
The procurement process shall be as follows:
The bids shall be opened and reviewed in accordance with the bid evaluation process and a notification of award shall be issued.
The Data Collection Contractor (DCC) shall mobilize the team as per the terms of the contract.
As part of the validation study, 100 km of surveys shall be conducted to confirm that the data can be processed and entered into the clients system.
The acceptance for actual survey shall only be issued after successfully completing the validation study including 100 km field survey.
If the data are not meeting the specifications then the DCC shall be given 30 days to rectify at the sole discretion of the Client.
If the DCC fails to meet the data specifications and calibration and validation requirements after the extension the Client shall declare the data and/or equipment non-comply and terminate the contract without any further extensions.
In the case of termination Client has the authority to negotiate and/or award the contract to the next ranked DCC.
2 COMMON SPECIFICATIONS
When measuring a number of different pavement condition parameters there are equipment and operational specifications common to all measurements. These common specifications are grouped together here.
2.1 TerminologyYes
It is recommended to define or describe the terminology used in the specifications. This ensures no ambiguity about the terminology used in the document.
Automated Data Collection: Fully automatic measurement and storage of data through electronic or mechanical measurements (e.g. profilometer measurements).
Semi-Automated Data Collection: Manual observations which are recorded into a computer as they are recorded (e.g. keyboard rating or voice recognition of defects).
Manual Data Collection: Manual observations and manual recording on paper which are later entered into a computer via keypunch operators (e.g. walk-over manual survey using data entry form and clipboard).
Road Network: A logical system of road links, sections and nodes.
Node: Nodes are used to mark points where traffic or road characteristics change. These include changes in traffic volume or composition, significant changes in geometry, road layout, population centres or administration boundaries. The first step in referencing a road network is to define the nodes.
Link: Links are a length of road joining two nodes. Typically, links are assumed to be homogeneous in terms of traffic.
Location Reference Point (LRP): These are intermediate points between nodes. LRP is a permanent object on or adjacent to the road which has been accurately located in terms of geo-coordinates and is used as a reference point for distance measurements. Segment: A segment is a length of road that is homogeneous in terms of its physical attributes or other features. It may also be defined for convenience, for example by breaking down a long link into more manageable shorter sections. The start and end of a segment is defined with a node or LRP (location reference point). Section: A section is a part of a road segment that has been subdivided into sections based on strong consistency in particular attributes such as geometry of the road, construction type, traffic and uniform distress. Accuracy: The ability of the survey equipment to measure the true condition of the item being surveyed. The aim is to reduce the equipment related bias or error in measurements if compared to more accurate measurements that has been taken before or has been taken with equipment being more accurate to that currently being used. Measurement Interval: The physical measurement interval used by the equipment. For example, roughness measurements using the laser profilometer records and stores the profile at every 25 mm. Reporting Interval: The minimum specified reporting interval at which the data is summarised for the Client. For example, roughness may be reported at 10 m or 20 m intervals for the same equipment as above. Dual Carriageway Road: A multi-lane road with or without a barrier or median separating traffic traveling in opposite directions.
Split Road: A road segment, which on some part and at a particular location is split from a single carriageway to dual/parallel carriageway.
Surface Area: Total section length multiplied by the carriageway width. This width excludes the paved shoulder width. Mandatory item is an activity/task that is required to be collected during the course of the project and its cost will be included in the financial evaluation.
Optional item is an activity/task that is additional/optional and may be collected during the course of the project and its cost will NOT be included in the financial evaluation. However, the DCC is expected to provide the cost details and Client at their own discretion can include some or all of these items in the data collection. and
2.2 Roles of the Parties to the ContractYes
A clear role description needs to be specified for each party involved with the contract. The client needs to specify what data would be supplied, who is responsible for quality assurance and what outcomes are expected of the DCC.
Client - the asset owner for whom the data is being collected.
Engineer or Client Representative (if applicable) - representative of the Client.
Data Collection Contractor (DCC) - normally responsible for data collection, data processing and quality assurance.
The Client Representative will ensure the Clients expectations in terms of the Contract are met. This includes ensuring the QA system is adhered to, the data is provided in the correct format and in accordance with QA requirements.
2.3 Term of the ContractYes
The terms of the contract specifies the actual duration of the contract, the frequency at which data has to be collected plus the duration of each survey round. The term of the contractor needs to reflect the Clients situation. Condition survey contracts can be from one to five years. The aspects the Client need to consider are:
Longer term contract gives DCC the opportunity to maximize their resources for the project and cheaper prices may be obtained. Furthermore, it is often found that a change in DCC leads to inconsistencies in the data.
The disadvantage of longer term contracts is normally as a result of a poor performing DCC. Once it is identified that the DCC cannot meet the contractual obligations it may be difficult to cancel the remaining portion of the term.
The best option is to have a hybrid contract that contains a fixed term, plus additional years for a good performing DCC. For example, the fixed term could be two years (say) and another two years could be secured if the DCC performs according to expectations.
The survey frequency will depend on the Clients objectives plus the nature of the network. For high volume roads (more than 1,000 vehicles per day) an annual survey is recommended. On lower volume roads a less frequent survey such as bi-annual may be adequate.The following aspects need to be specified.
The Contract term is 2 years plus two one year extensions;
The survey frequency for the entire network will be annually If different for different parts of the network, specify the criteria and conditions required .
2.4 Data RequirementsYes
The purpose and the intended use of the data to be collected shall be clearly identified prior to finalizing the specifications. The topdown approach is recommended where the intended use of the data will drive the data requirements and their accuracy. The accuracy of the data can be expressed in terms of Information Quality Levels (IQL) defined in a World Bank Technical Publication by Paterson and Scullion (1990). IQL allows to structure road management information in ways that suit the needs of different levels of decision making and the variety of effort and sophistication of methods for collecting and processing data.
The precision of the data to be collected shall be based on the World Banks Information Quality Level (IQL) concept, as shown below.
In road management five levels of data have been identified as given below.
IQL Level
Precision / Detail1
Most comprehensive level of detail, such as would be used as a reference benchmark for other measurement methods and in fundamental research. Would also be used in detailed field investigations for an in-depth diagnosis of problems, and for high-class project design. Normally used at project-level in special cases, and unlikely to be used for network monitoring. Requires high level of staff skills and institutional resources to support and utilise collection methods.2
A level of detail sufficient for comprehensive programming models and for standard design methods. For planning, would be used only on sample coverage. Sufficient to distinguish the performance and economic returns of different technical options with practical differences in dimensions or materials. Standard acquisition methods for project-level data collection. Would usually require automated acquisition methods for network surveys and use for network-level programming. Requires reliable institutional support and resources.3
Sufficient detail for planning models and standard programming models for full network coverage. For project design, would suit elementary methods such as catalogue-type with meagre data needs, and low-volume road/bridge design methods. Able to be collected in network surveys by semi-automated methods or combined automated and manual methods.4
The basic summary statistics of inventory, performance and utilisation, of interest to providers and users. Suitable for the simplest planning and programming models, but for projects is suitable only for standardised designs of very low-volume roads. The simplest, most basic collection methods, either entirely manual or entirely semi-automated, provide direct but approximate measures, and suit small or resource-poor agencies. Alternatively, the statistics may be computed from more detailed data.5
Represents a top level such as key performance indicators, which typically might combine key attributes from several pieces of information. Still higher levels can be defined when necessary.Refer to Guidelines on Calibration and Adaptation, HDM-4 Technical Reference Series, Volume 5 by Bennett, C.R. and Paterson, W.D.O. (1999) for a complete discussion of Information Quality Levels (IQL) and their application to road data collection.The data precision required is given in Section 2.5.
2.5 Data to be Collected Yes
The data items required for data collection must be determined before the specification is prepared. The paper Data Collection Technologies for Road Management published by the World Bank details the types of data used for road management and the different technologies available to collect the data. The issues discussed in this report should be fully understood before developing the procurement specification. Questions which should be utmost in the mind when preparing specification are:
What is the end use for the data. For example, the data may be used for reporting purposes to a funding body or, the data is used to make maintenance planning decisions. What type of network is being measured.Is the technology selected applicable to this network.What do we need to measure.Among the factors that should be considered are:
Where the network is very rough or is unsealed then laser technology for measuring roughness is not appropriate.
Where a network is primarily concrete and is less susceptible to rutting, do you need to measure transverse profile?
Where the network is small, has low volume traffic and the maximum speed on the network is 50km/h is there a need to measure skid resistance?
In situations of constrained funding the importance of the data items needs to be prioritised and selected according the availability of funding.
From the following list, include only those data types deemed necessary for your particular network. The data to be collected is specified by pavement type (paved/unpaved) and Client can agency can modify this to suit to their requirements such as road classification or a combination of pavement type and road classification.
The following data is required for this contract.Data Item
Units
Reporting IntervalMin Accuracy LevelPavedUnpavedLocation Referencing
Location referencing (linear)
-0.1%M/O/NRM/O/NRGPS Centreline coordinates
-5/10/20m
5/10m - horizontal
M/O/NRM/O/NRInventory
Road Inventory
Road Type
-
when change occursIQL 2/3/4M/O/NRM/O/NR Pavement Surface Type
-
when change occursIQL 2/3/4M/O/NRM/O/NR Pavement Width
m
when change occursIQL 2/3/4M/O/NRM/O/NR Shoulder Width
m
when change occursIQL 2/3/4M/O/NRM/O/NR Shoulder Type
-
when change occursIQL 2/3/4M/O/NRM/O/NR Shoulder Elevation
cmwhen change occursIQL 2/3/4M/O/NRM/O/NR Median Width
mwhen change occursIQL 2/3/4M/O/NRM/O/NR Side Ditch Type
-when change occursIQL 2/3/4M/O/NRM/O/NR Side Ditch Elevation
cmwhen change occursIQL 2/3/4M/O/NRM/O/NRRoad Furniture Barriers1%M/O/NRM/O/NR Signs1%M/O/NRM/O/NR Street Lighting1%
M/O/NRM/O/NRLand Use Type
-when change occursM/O/NRM/O/NRGeometry
M/O/NRM/O/NR Horizontal Alignment
O10/20/100/1000 mIQL 2/3M/O/NRM/O/NR Vertical Alignment
%10/20/100/1000 mIQL 2/3M/O/NRM/O/NR Transverse Gradient
%10/20/100/1000 mIQL 2/3M/O/NRM/O/NRCondition
Pavement Roughness
IRI
10m - laser
100m/200m - BI
IQL 2/3/4M/O/NRM/O/NRSurface Condition Index / Surface Distress Index / Surface Integrity Index
num
100m/200mIQL 2/3/4M/O/NRM/O/NRPavement Edge Damage
%
100m/200mIQL 2/3/4M/O/NRM/O/NROther Defects Cracking
%100m/200mIQL 2/3/4M/O/NRM/O/NR Potholing
num100m/200mIQL 2/3/4M/O/NRM/O/NR Ravelling
%100m/200mIQL 2/3/4M/O/NRM/O/NR Patching
%100m/200mIQL 2/3/4M/O/NRM/O/NR Depressions
%100m/200mIQL 2/3/4M/O/NRM/O/NR Bleeding
%100m/200mIQL 2/3/4M/O/NRM/O/NRRut Depth
mm
10m/20mIQL 2/3/4M/O/NRM/O/NRShoving
mm
10m/20mIQL 2/3/4M/O/NRM/O/NRSurface Texture
num
10m/20mIQL 2/3/4M/O/NRM/O/NRSkid Resistance
num10m/20mIQL 2/3/4M/O/NRM/O/NRShoulder Condition
num100m/200mIQL 2/3/4M/O/NRM/O/NRSide Drainage Condition
num100m/200mIQL 2/3/4M/O/NRM/O/NRMulti Media
ROW Video Logging
-5m/10m800 x 600 pixelM/O/NRM/O/NRDigital Images of LRPs
-M/O/NRM/O/NRDigital Images of Bridges
-M/O/NRM/O/NRPavement Structure
Structural Deflection
mm200m/500mM/O/NRM/O/NRLayer Modulus
200m/500mM/O/NRM/O/NRPavement Composition
200m/500m if NDT
1km/5km if DCPM/O/NRM/O/NRTraffic
Manual Traffic Counting
vpdM/O/NRM/O/NRAutomated Traffic Counting
vpdM/O/NRM/O/NRCross Drainage Structures
Location
mIQL 2/3/4M/O/NRM/O/NROverall Condition
NumIQL 2/3/4M/O/NRM/O/NRM Mandatory; O Optional; NR Not Required; vpd vehicles per day.
2.6 Survey NetworkYes
This is where a detailed description of the network to be surveyed should be included. This should list all factors that might influence the data collection. For example if the network is residential, or has significant volumes of slow moving traffic (horse drawn carts) then the minimum survey speed may be a consideration in selecting data collection equipment. The length of the network should be broken down by surface type and/or road classification.
It is advised to include information on terrain or topography of the network.
The following is the distribution of the road network by pavement type:
Type
Length (km)
Lane Configuration
Topography
Bituminous
xx
NA
1 Lane xx km
2 Lane xx km
4 lane xx km
NA
Flat xx%
Rolling xx%
Hilly xx%
Portland Cement Concrete
xx
NA
1 Lane xx km
2 Lane xx km
4 lane xx km
NA
Flat xx%
Rolling xx%
Hilly xx%
Unpaved
xx
NA
1 Lane xx km
2 Lane xx km
4 lane xx km
NA
Flat xx%
Rolling xx%
Hilly xx%
TOTAL
xx
NA
1 Lane xx km
2 Lane xx km
4 lane xx km
NA
Flat xx%
Rolling xx%
Hilly xx%
In terms of road classes, the following is the distribution of the network:
Type
Length (km)
Lane Configuration
Topography
Urban
xx
NA
1 Lane xx km
2 Lane xx km
4 lane xx km
NA
Flat xx%
Rolling xx%
Hilly xx%
Expressway
xx
NA
1 Lane xx km
2 Lane xx km
4 lane xx km
NA
Flat xx%
Rolling xx%
Hilly xx%
Rural - Paved
xx
NA
1 Lane xx km
2 Lane xx km
NA
Flat xx%
Rolling xx%
Hilly xx%
Rural - Unpaved
xx
NA
1 Lane xx km
2 Lane xx km
NA
Flat xx%
Rolling xx%
Hilly xx%
TOTAL
xx
NA
1 Lane xx km
2 Lane xx km
4 lane xx km
NA
Flat xx%
Rolling xx%
Hilly xx%
2.7 Special InstructionsYes
Special instructions of the following nature shall be mentioned in the specifications. Include only those features which influence the schedule and/or the quality of the project deliverables.
Flooding / snowing seasons;
High temperature requiring special attention in the field work;
Sensitive areas;
Any other feature that is unique to the network such as existence of Landmines within ROW etc.
Preferred timing of surveys may be specified. For example, if there is a specific season in which surveys are normally conducted. It is good policy to specify repeat surveys to be undertaken during the same time each year.
The following are special issues that require DCCs attention while preparing their proposal. Heavy floods/ monsoon season forecasted between June and October;
Summer temperatures can exceed 400C;
Snow fall in December.
and
The above are given for information purpose only and DCC shall source the information required to prepare their proposal.
2.8 Survey Header DataYes
The following items must be recorded with or linked to each of the specific data items detailed in Chapter 3. Include all information necessary to link collected data.
Survey date (and time of day if possible); Description of section; Vehicle ID, Crew ID; Weather conditions; Run number; Travel speed; Direction of survey relative to reference direction (increasing/decreasing); Lane number or transverse position on road (optional).
2.9 Survey EquipmentYes
The equipment specifications are beyond the scope of this document. It is recommended that the TOR for data collection not specify and/or prefer a particular type of equipment or manufacturer. The emphasis should be on the collection of data items to the required precision. However, it is recommended to enforce DCC using fit for the purpose equipment.
Most survey equipment uses specialized computer algorithms to process and record data (e.g. calculate IRI from the raw profile). The Client may not specify these algorithms but for all the relevant equipment the DCC must disclose what algorithms are used.
The DCC is free to make their own choice of equipment for the data specified to be collected. However, the equipment selected must be of a robust design capable of operating under the expected local conditions.
All survey equipment used for data collection should fully be functional at normal local highway speed on both urban/rural roads and expressways/highways included in the network, and be capable of measuring on both bituminous and concrete pavements where the predominant pavement type will be bituminous/concrete roads.
It is required to use the latest version of the software released by the equipment manufacturer. All beta or test versions are excluded.
If the DCC choose an earlier version of the software then they must justify in their technical proposal on why and how no added benefits are perceived from using the latest version compared to that proposed.
DCC shall disclose the algorithms used for all relevant equipment. For example profile processing algorithms used by their proposed laser profilometer for calculating roughness.
2.10 Contractor Skills
Yes
The contract specifications should specify that all staff nominated by the DCC should have relevant experience and training in order to perform the assigned task for the condition measurements. This will not only ensure a better end product but will also prevent unnecessary rejection of poor quality work.Most of the equipment use for automated data collection are specialized equipment and the staff should as a minimum be skilled to perform: Knowledge of calibration and daily check of the equipment;
Ability to check the data;
Understand the principle of the measurements such as roughness and rutting;
Awareness of the importance of items that influence the results such as events;
Working knowledge of the equipment limitations where measurement becomes unusable (e.g. weather conditions or measurement speed).
The DCC must demonstrate that all staff have the required training and experience using the equipment they are assigned to use. Only staff members approved by the Client or Client Representative will be allowed to work on the contract. Staff are approved during the equipment calibration and validation process. All DCC staff must be trained or skilled in all policies and work practices adopted by the Client. (e.g. traffic control requirements etc).
2.11 Survey ProcedureYes
From a data quality point of view it is better if all data is collected in a single pass using one host vehicle, this minimizes location referencing and other problems. However the network size and or the time constraints may necessitate the use of multiple teams and or passes. Where the DCC chooses to complete the survey in multiple passes or using multiple vehicles the contractor must demonstrate that data collected using multiple surveys or equipment can be matched to the road furniture and road features.It is recommended that at least one observer from the Client organization work with the DCC while the survey is being conducted. This provision should improve identification of roads and reference points, speed data collection and improve accuracy.
Where semi-automated methods, such as visual inspections, are proposed by the DCC the consistency between and within multiple survey teams must also be demonstrated.
Different lateral positioning of the survey vehicle are provided for measuring single, dual and divided carriageways. The contract should specify the preferred option. It is also important to maintain consistency throughout the duration of the contract. I.e. the same location has to be measured for subsequent surveys.
Where the DCC chooses to use two or more survey vehicles or to complete the surveys in multiple passes then the survey equipment and operators must undergo additional validation to demonstrate that all data can be matched to the same road furniture and road features. The proposal shall also include details on how the surveys will be conducted and the order of surveys.
Unless specified all surveys are to be conducted in the direction of increasing km post. Irrespective of the survey direction, all data are to be referenced in terms of increasing km post and chainage.
The standard survey procedures shall be:
On narrow single carriageway roads: the survey vehicle travels in the direction of increasing chainage, with the measurements taken in the normal driven wheelpath. Note where roads are particularly narrow this is likely to straddle the road centerline. Data processing techniques should account for instances when the vehicle deviates from the road onto the shoulder. On single carriageway, 2-lane roads: The DCC will survey both increasing and decreasing lanes/ increasing lane only . The measurements will be taken in the wheelpaths; where no obvious wheelpath is visible the measurements will be taken 50 70cm from the edge of the pavement. On divided carriageway roads: The DCC will survey both increasing and decreasing lanes/increasing lane only . The measurements will be taken in the wheelpaths; where no obvious wheelpath is visible the measurements will be taken 50 70cm from the edge of the pavement. On dual carriageway roads: The DCC will survey all lanes/both increasing and decreasing lanes/ increasing lane only . The measurements will be taken in the wheel paths; where no obvious wheelpath is visible the measurements will be taken 50 70cm from the edge of the pavement. Where GPS coordinates are specified the DCC will ensure the coordinates are offset so that the road centreline is obtained. Note the method chosen for this offset by the DCC must be agreed by the Client.
The collection of inventory, road furniture and surface integrity data (potholes, cracking, raveling, flushing, patching, and depressions) may be recorded using semi automated means, however if the DCC chooses this method they shall clearly elaborate the method and procedures that will be used for the semi automated visual surveys, if employed. Particular emphasis must be placed on how quality control will be ensured with these data items and, if separate surveys are used, how location referencing problems shall be reconciled.
Data collection activities should be restricted when the road surface is wet, contaminated with debris or when the temperature is outside the specified limits.
2.12 Location Referencing SystemNo
A fixed Location Referencing System (LRS) should be used for all data collection. The Client should notify the DCC if an LRS already exists or recommend their preference for the development of a new LRS. An example is given below for specifying the location referencing system.
The data items will be referenced using the following Location Referencing System (LRS): Province Number (2 digit character as provided);
Road Number (as provided);
Link suffix (optional 3 digit number)
Km Reference (chainage/distance measurement)
The Client can ask DCC to propose an appropriate LRS either in the technical proposal or before the survey starts. There is no general description for the LRS and therefore it is recommended to review on case by case basis.
2.13 Equipment to be Provided by ClientNo
Client can provide equipment to DCC for collecting the data specified. This not only reduces the cost of data collection but also provides a sense of comfort for the Client that appropriate equipment is used on the project. Client knows upfront what to expect out of the project.However, there is a risk that the equipment may be faulty or may become non-functional during the course of the survey. This will shift the major risk to Client agency in ensuring the equipment is functional at all times for the duration of the survey.
It is recommended that Client only provide equipment only when they are certain and have sufficient support or resources to ensure the equipment is functional at all times. There is no general description for the equipment provision and therefore it is recommended to review on case by case basis.
The client will not provide any survey equipment.
2.14 Equipment to be Provided by ContractorYes
Client can specify in the TOR for turn over of the equipment or can reserve the right to negotiate with DCC at the end of the surveys. The latter provides flexibility to Client agency to assess the equipment used for the project.
The DCC will provide all equipment needed to complete the survey.
As part of technology transfer and capacity building, the Client reserves the right to negotiate with DCC for the purchase of one complete set of data capture and processing equipment with required licensed software, operating manuals, and clear step-by-step procedural written instructions and/or training videos; including the vehicle in which the survey equipment will remain mounted.
2.15 Data FormatYes
The particular requirements for each road management system (RMS) can be quite different, and therefore it is best to specify a particular data format that is compatible with the Agencys system. There may also be some accumulated result or specific statistical results that are peculiar to Clients RMS requirements (e.g. data averaged per 100 m) and this is where these items can be defined.
If possible, the specification should include precise details on the RMS or database that will be used to store the data. The client may choose to provide template files to further define the data format and then specify that data matches these templates. The more information provided, the easier it will be for the DCC to ensure that they can successfully interface with your RMS. The Agency must also recognize that, depending on the RMS in use, it may be necessary for the RMS supplier to modify or update their system to make use of the data from the equipment.
If the Agency does not have an existing RMS it is useful for the specification to include the provision of, as a minimum, a simple database program for storing and using the data. Should the Agency be interested in a full RMS, reference should be made to the generic Terms of Reference for the Supply and Installation of a Road Management System available for download from www.road-management.info.
All data must reflect the standard practice of driving on the left/right . All data algorithms must be agreed by the Client.
Two levels of data are required Raw Data, and Detailed Data: Raw data is the record of the individual measurements taken by the survey equipment and must be provided in ASCII delimited format or other format agreed by the Client. Raw data detail must be retained such that the detailed and aggregated data can be recalculated.
Detailed data is processed raw data summarised at 10 to 100 m intervals formatted so that it can be loaded into the database.
The equipment shall be able to produce export files in an industry standard format e.g. comma separated values, MS Access, MS Excel, DBF etc .Note a full description of the data reporting interval and format for each data type is detailed in Chapter 3.
If the Agency has an existing RMS The data will be stored in the Agencys road management system (RMS). This RMS was supplied by . The current version of the software is and includes the following modules . The software is/is not under a current maintenance and support agreement with the software vendor. Data should conform to .
3 DATA COLLECTION SPECIFICATIONS
3.1 Location ReferencingYes
Correct location referencing is considered to be a key element of all road management systems. Where no location referencing system exists the DCC will be required to establish and define Location Reference Points. This may be undertaken as a Location Reference Point (LRP) survey on project links prior to other surveys. The LRP survey can be collected simultaneously with a video logging and GPS centerline survey.
Three possible scenarios exist as follows:
Location Referencing data does not exist This is a straight forward scenario where Client can ask the DCC to establish the location reference points and collect LR data.
Location Reference data exists, but needs updating This happens when the available LR data is outdated and needs updating. This can be achieved by defining a new set of LR data or using the available LR data and updating where required. Location Referencing data exists, needs no updating This is again a straight forward scenario where DCC has to use the LR data made available to them.It is advised to mention the likely scenario from the above list. Where existing LR data needs updating it is recommended that the Client define which portion needs updating and to what extent.
A general description of the services is given below for three scenarios and Client shall select the suitable scenario or combination of scenarios by deleting others.
Location Referencing data does not exist Define each road, locate and define the start and end point, establish the nodes and intermediate Location Reference Points (LRP). The nodes and LRPs must be defined by both chainage and GPS coordinates. Each road link beginning and end must be defined as a node and located at a major intersection. Each LRP must be an easily identifiable permanent reference point in the field, also defined by chainage and GPS coordinates. In many instances these will be based upon the existing km posts or, if km posts are missing, other fixed points (Bridges, Culverts) adjacent to the carriageway. When there are no km posts or LRPs the maximum distance between LRPs shall be 5 km.
The offset direction and the LRP numbers should increase in terms of increasing km post numbers. If there are no km posts on a road, the LRPs should be defined as increasing from the larger city to the smaller city.The locations will be identified to an accuracy of 1.0 m or better.
The DCC must detail their equipment capability and proposed methodology for defining LRPs.
Location Reference data exists, but needs updating The existing nodes and LRPs with their offset chainages shall be supplied to DCC in .dbf/.mdb/text format. This information must be used when collecting other specified data items. DCC shall review, update and collect where missing location referencing data for paved/unpaved roads. It is estimated that 1,000 Km of road length needs LR data updating. DCC must always reset the chainage to 0 at each LRP.The DCC must measure the distance and offsets when other data is collected. The allowable distance measurement error is 0.1%. Therefore two possible scenarios exist:
Where there is a discrepancy in distance measurement, but it is within the allowable error limit - The measurements shall be appropriately scaled to match the total length provided by the Client. This scaling factor shall be determined for each road section (between two LRPs) and this factor shall be used to scale the length within the road section .
Where there is a discrepancy in distance measurement and this exceeds the allowable error, the DCC must re-survey the road/link . If the second survey confirms the initial survey, the DCC must notify the Client immediately. The DCC must confirm the accuracy of the current distance measuring instrument (DMI) and where this is within tolerance the DCC may continue the survey. Where the DMI is not within tolerance the DCC must develop a remedial proposal for agreement with the Client. If the distance discrepancy remains consistent on other links the Client will consider establishing a new set of LR data.
The DCC must detail their equipment capability in handling and updating the pre-defined LR data.
Location Referencing data exists, needs no updating The existing nodes and LRPs with their offset chainages shall be supplied to DCC in .dbf/.mdb/text format. This information must be used when collecting other specified data items. DCC must always reset the chainage to 0 at each LRP.The DCC must measure the distance and offsets when other data is collected. The allowable distance measurement error is 0.1%. Therefore two possible scenarios exist:
Where there is a discrepancy in distance measurement, but it is within the allowable error limit - The measurements shall be appropriately scaled to match the total length provided by the Client. This scaling factor shall be determined for each road section (between two LRPs) and this factor shall be used to scale the length within the section . Where there is a discrepancy in distance measurement and this exceeds the allowable error, the DCC must re-survey the road/link . If the second survey confirms the initial survey, the DCC must notify the Client immediately. The DCC must confirm the accuracy of the current distance measuring instrument (DMI) and where this is within tolerance the DCC may continue the survey. Where the DMI is not within tolerance the DCC must develop a remedial proposal for agreement with the Client. If the distance discrepancy remains consistent on other links the Client will consider establishing a new set of LR data. The DCC must detail their equipment capability in handling pre-defined LR data.
Distance Measurement
The DMI transducer must be installed on the survey vehicle so that the distance measurement replicates the road centerline (on the wheel nearest to the road centre) this will minimize the loss of accuracy due to turning movements.
All distances shall be measured using a distance measurement device with an accuracy of 0.1% or better. The positions of LRPs and other important marks (e.g. intersections, railway crossings) shall be expressed as offsets from the previous LRP or node. Chainages are measured continuously from the start to the end of the link. At each node and LRP the offset must be reset to 0. Thus, all distances between LRPs are expressed as the offset from the previous LRP.
3.2 GPS Centerline CoordinatesYes
The road centerline is a notional reference line that generalizes and approximates the true centerline of the road to an accepted and known accuracy. It is not meant to be a tool for engineering design but rather as a tool to spatially locate attribute information and graphically represent the network.The road centerline is collected by recording the GPS coordinates of the survey vehicle fitted with a GPS receiver as it is driven along the road. The data can be offset so that the position recoded approximates the road centerline. The rate the data is collected and data accuracy is dependant on the type of receiver used.
Points to note:
Data accuracy is dependant on field and atmospheric conditions and the location and number of satellites available. Data can be corrected to minimize this inaccuracy by simultaneously recording coordinate data at a fixed known reference. This data can then be used to correct the collected data.
Two options are available:
Uncorrected Data Raw data collected by the GPS receiver.
Differentially Corrected Data Raw data which has been corrected using data collected from a base station. Note this can be corrected while the data is being collected using a correction data stream such as Omnistar or post processed in the office.
The main difference in achieving higher accuracy is cost.
Data collection rate is also important, for example collecting data at 1 second intervals will give on point every 20m when the survey vehicle is traveling at 72km/hr. Currently receivers can collect data at up to 10 samples per second, but again the higher the rate the more expensive the system.
GPS signal can be lost when traveling under trees or near large buildings, or when the position of the satellite is not favorable.A GPS Centerline may not be required for all systems but given that most automated data collections system also include GPS capabilities at little extra costs, it is advisable to have a GPS Centerline. This will allow Geospatial display of data once the survey is completed.
The road centerline is a notional reference line that generalizes and approximates the true centerline to an accepted and known accuracy. The geo-coordinates of the nodes, LRPs and centerline shall be recorded and reported in uncorrected/corrected for differential positioning format. The data are to be provided in a mapping coordinate system that is agreed with the Client before the survey commences.
Uncorrected
The DCC must offer uncorrected, 95% 10.0/20.0/30.0 meter horizontal and 95% 10.0/20.0/40.0/60.0 meter vertical accuracy, or better GPS data.
Differentially Corrected The geo coordinates shall be measured using either real time differentially corrected Global Positioning System (DGPS) equipment or post processed for differential correction. The DCC must offer differentially corrected, 95% 1.0/3.0/5.0 meter horizontal and 95% 1.0/3.0/5.0 vertical accuracy , or better GPS data. DCC must specify the differential correction data source and methodology used.The GPS referencing should be made as close to the road centerline as is practical. The reference for altitude has to be made at the pavement surface. The DCC shall supply the geo-coordinates continuously at no less than every 5.0/10.0/20.0 meter, at the road centerline. In the case of a divided carriageway, the location data shall be that describing the centerline of the carriageway. All centerlines must have the correct and complete topology (e.g. intersecting roads must intersect) and a unique centerline shall be provided for each link.
The DCC shall describe in their technical proposal the methodology proposed to establish the road centerline. This shall include discussions on, but not be limited to, how the data will be collected; real-time or post-processed differential correction method ; correction of data anomalies (e.g. loss of GPS signal, gyro drift over time, satellite downlink DGPS etc.), data processing and reconciliation of data with LRP survey co-ordinates.
3.3 Road InventoryYes
Road inventory contains those items which are comparatively static in nature i.e. they usually dont change with time unless there is some activity or construction done on them. These data items need only to be collected once and then checked on a 3 or 5 year basis.
Road inventory data shall comply with IQL-2/IQL-3/IQL-4 for all roads, unless otherwise agreed with the Client. These data items shall be reported when there is a change in the particular attribute.Road Type Every road link must be categorized into one of the five types detailed below or as agreed by the Client before the survey starts: Single lane
Intermediate lane
Two lane
Four lane without divided carriageway
Four lane with divided carriageway
This data item may be recorded in the field or can be estimated from other data items collected in the field, such as ROW Video or pavement width.Pavement Surface Type The pavement surface type will be categorized as agreed with the Client before the survey starts. As a minimum DCC must record using one of the five types given below:
Asphalt concrete
Surface treatment
Cement concrete
Gravel
Earth
It is recommended to record HDM-4 compatible pavement types in the field.
Pavement Width The DCC shall indicate how the pavement width data will be acquired and the accuracy of the measurements. As a minimum, it is required to identify widths in the bands:
< 4.5 m
4.5 m - 6.0 m
6.0 m - 7.5 m
7.5 m - 9.0 m
> 9.0 m
The final width bands shall be agreed with the Client before the survey starts. Shoulder Type The shoulder type will be recorded using the codes to be agreed with the Client before the survey starts. As a minimum it shall be recorded as:
Paved
Gravel
Earth
Shoulder Width Shoulder width is to be recorded for both the left and right side shoulder using the following bands:
No shoulder
< 1.0 m
1.0 m - 2.0 m
> 2.0 m
The final width bands shall be agreed with the Client before the survey starts.
Shoulder Elevation The DCC is to monitor the difference in elevation between the shoulder and the pavement edge. The DCC shall define if it is higher, level, or lower than the pavement edge.
Median Width As a minimum, the median width data shall be recorded in the bands:
No median
< 1.0 m
1.0 m - 3.0 m
3.0 m - 5.0 m
> 5.0 m
The final width bands shall be agreed with the Client before the survey starts.
Side Ditch Type The type of the side ditch is to be recorded for both the left and right side using the codes to be agreed with the Client before the survey starts.
Side Ditch Elevation The side ditch elevation is to be recorded for both the left and right side using the codes to be agreed with the Client before the survey starts.
Cross Section The cross-section of the roadway should indicate whether it is a cut or fill, on embankment.
Topography The DCC shall define or record the topography as agreed with the Client before the survey starts. As a minimum the topography must be recorded as:
Flat Rolling
Hilly
The topography is recorded in the field/determined from the GPS data .
Road Furniture The DCC shall record the location and type of the road furniture for urban/rural roads. The type of road furniture to be collected shall be agreed with the Client before the survey starts. As a minimum the following must be recorded: Barriers
Signs
Street Lights
The start and end location shall be recorded for street lights.
Land Use Type The land use type for each road link shall be recorded as agreed with Client before the survey starts. As a minimum the following must be recorded:
Residential
Commercial
Industrial
Agricultural
Water bodies
Public/community use
Mix land use (with categories)
3.4 GeometryYes
Road Geometry is also comparatively static in nature, and only changes when the road is reconstructed or realigned. The level of detail required will dictate the measurement/device type to be used. Automated data collection devices may be used for IQL-2 accuracy where visual observations or GPS data, if collected/available can be used for IQL-3 details. General specifications for both IQL-2 and IQL-3 levels are given below, select as appropriate.
IQL-2 Level The specified data are to be measured using automated continuous devices.Data Type
Parameter to Report
Units
Accuracy
Reporting Interval (m)
Horizontal Alignment
Heading
degrees
5%
10/20/100/1000
Radius of Curvature
m/1/m
5%
10/20/100/1000
Vertical Alignment
Grade
%
5%
10/20/100/1000
Transverse Gradient
Crossfall
%
5%
10/20/100/1000
IQL-3 Level Visual observations/GPS data shall be used to define the specified data items below.
Horizontal Alignment The horizontal alignments shall be reported using the 4 classes given below, or as agreed with the Client before the survey starts:
Straight Fairly straight Curvy Winding
Vertical Alignment The vertical alignments shall be reported using the 4 classes given below, or as agreed with the Client before the survey starts:
Flat Rolling Moderate Mountainous
3.5 ConditionYes
Pavement condition includes those data items which change over time with or without any work done. These data items are required to be measured at regular intervals, say on an annual basis to monitor change and to provide an accurate estimate of the overall condition of the network.
Condition data can be divided into two different types, those collected by fully automated means, roughness, rutting, texture, skid resistance etc. and those collected using semi-automated or manual methods, the surface distress items such as cracking, flushing, potholes etc. A general description is given below for all possible condition data items. Where a condition data item can be measured by more than one technique such as roughness both methods are included and the most appropriate method should be selected by Client agency. Most commonly used techniques are listed below and it is advised to include only those items and techniques which are relevant the network considered.
The laser profilometer requires specialized software algorithms for the processing of raw data in order to yield IRI. The Client must specify the method to be used or get DCC to specify it in their Quality System subjected to approval from the Client.Two methods are available to determine the surface distresses - A composite index can be recorded in the field indicating the surface condition, the composite index can then be converted into individual distresses through a transfer function. Alternatively individual distresses can be recorded in the field and a single parameter/indicator can be estimated defining the overall surface condition using the individual distresses. Finalizing the composite index may be out of the scope this contract. It is advised to choose and include one method that is appropriate for the purpose.
Pavement Roughness Laser Profilometer The DCC should use a Class 2 or better Laser Profilometer to measure longitudinal profile. The DCC shall record and report the longitudinal profile data and process the profile data to provide and report International Roughness Index (IRI) in m/km. The DCC must seek approval from the Client on the profile processing methodology used. The DCC that offers a system with the ability to measure roughness under Stop and Go will be given preference. The data shall be recorded as follows:
Wheelpath : one/two
Profile sampling interval : no more than 25 mm
IRI reporting interval: no less than 10 m
Factors which may influence IRI shall be recorded during the survey and the data corrected accordingly. These include, but are not limited to, traffic congestion, pavement construction activities, having to travel off the carriageway, etc. There are some practical operation practices that the operator should avoid such as sudden acceleration or braking during surveys. Some situations in urban areas may cause poor data and where survey speeds cannot be maintained the DCC shall notify these sections with the cause. Client shall suggest DCC the remedial action. Some examples may include, omitting these streets from the survey or doing a manual assessment of the roughness. If road conditions are be found in some areas to be so extremely rough that collection of roughness data in the above mentioned manner is not practical or safe; the DCC shall provide a means for estimating pavement roughness for use in such areas, calibrated by ASTM E 1364-95 or a similarly acceptable standard, and subject to Client approval.Pavement Roughness Response Type Roughness Meter The roughness data shall be collected using one/dual response-type roughness meters or similar. The instrument shall be calibrated to the International Roughness Index (IRI) expressed in m/km in accordance with ASTM E 1448-92/98. The roughness data shall be reported on no more than a 100/200 meter interval. The speed shall be recorded during the survey and taken into account when calculating the IRI from the raw data.
Factors which may influence the IRI shall be recorded during the survey and the data corrected accordingly. These include, but are not limited to, traffic congestion, pavement construction activities, having to travel off the carriageway, etc.
If road conditions are be found in some areas to be so extremely rough that collection of roughness data in the above mentioned manner is not practical or safe; the DCC shall provide a means for estimating pavement roughness for use in such areas, calibrated by ASTM E 1364-95 or a similarly acceptable standard, and subject to Client approval.
Surface Condition The surface condition shall be expressed using an IQL-3 index such as the Surface Integrity Index (SII). The data shall be collected at no more than 100/200 meter intervals, referenced to the last LRP.
Note: The SII combines assessments of the incidence, severity and modes of distress in a numeric score from 0 (representing no defects) to 5 (representing obstructive defects). It is defined in the following table, which is the basis on which the visual estimation and survey are to be conducted.
Score
Incidence of Minor Defects
Incidence of Major Defects
0
None
None
1
1 to 20 m2 per 100 m
or
1 occurrence
2
< 50% of the area
or
2 to 4 occurrences
3
> 50% of the area
or
< 30% of the area
4
N/A
30% area, or eroded base on up to 20% of the area
5
N/A
Eroded base on more than 20% of the area
The defects are defined for bituminous roads as follows:
Minor Defects: Narrow interconnected cracks (1-2 mm width), any line cracks, shallow ravelling (100 mm), rut depth >15 mm, corrugations, potholes.
Eroded base: Full loss of surfacing and partial loss of base material.
The most prevalent form of distress on the section will be noted by a single code or word, e.g. CR-cracking; PH-potholes; DF-deformation; DI-disintegration; EB-edge break; PA-patching.
During data reduction, the SII value can be translated to a general condition class as follows: 0 and 1 = Good; 2 and 3 = Fair; 4 and 5 = Poor.
To ensure consistency in the visual rating process, the DCC must document their visual assessment procedure. This shall include definitions of the distresses, how they are to be measured, and have photographs to guide the raters. This must have Client approval before data collection can commence.
The DCC shall also prepare transfer functions which will convert the IQL-3 measured SII into individual distresses. DCC shall also give details on how these functions are developed.
Surface Distresses The DCC shall collect the following surface distresses at 100/200 meter intervals, referenced to the last LRP:
Cracking in % of the surface area
Ravelling in % of the surface area
Potholes in number
Disintegration in % of the surface area Depressions in % of the surface area
Bleeding in % of the surface area
Patching in % of the surface area
The DCC shall to indicate which of these data items are able to be collected and how they will be collected in their technical proposal.
To ensure consistency in the visual rating process, the DCC must document their visual assessment procedure. This shall include definitions of the distresses, how they are to be measured, and have photographs to guide the raters. This must have Client approval before data collection can commence.
Pavement Edge Damage Pavement edge damage is defined as edge break or kerb damage. The data are to be described in terms of extent and severity as a percentage of the length damaged. The data are to be collected over 100/200 meter intervals.
Rut Depth The transverse profile is to be measured using non-contact sensors. The rut depth is to be expressed as the maximum vertical depth in mm for each wheel path under an equivalent 1.2/2.0/3.0 meter straight edge. Measuring width no less than 3200 mm Vertical resolution 0.5 mm
Minimum number of measurements per profile 13
Distance between measurement locations across profile 200 mm to 400 mm
Reporting interval 10/20/100 m
Data to be reported as mean and std deviation of left and right wheelpath rut depth
The DCC shall describe the configuration of their system in the technical proposal. The DCC must disclose the data processing algorithm to the Client for approval.Shoving The shoving is to be determined from the transverse profile measured. The shoving is expressed as the maximum vertical depth in mm for each wheelpath. The data are reported over 10/20/100 meter interval.Surface Texture The texture will be calculated for each wheel path using non-contact sensors. The macro texture will be presented as the Root Mean Sensor Texture Depth (RMSTD) and/or the Mean Profile Depth (MPD).
Reporting interval 10/20/100 m intervals. Vertical resolution 0.01 mm.
Sampling interval no less than 0.5 mm.
The DCC shall be required to provide a method for converting the value to the Standard Sand Patch/Sand Circle Volumetric Method compatible with ASTM standard E1845-01 Standard Practice for Calculating Pavement Macrotexture Mean Profile Depth.Skid Resistance The skid resistance data shall be recorded using a portable, trailer mounted system. Skid Resistance is recorded simultaneously with pavement texture and road geometry to enable the International Friction Index (IFI) to be calculated and investigation levels applied as required. Measurement type continuous/sampled
Reporting interval 10/20/100 m
Reported Parameter SFC/IFI Measurements are to be undertaken for 1,000 km on pre-selected sections of the network where skid resistance is considered to be a problem/on the entire network . The locations will be agreed with the Client before survey starts.
Shoulder Condition The shoulder condition shall be recorded as per requisite IQL for both the left and right side shoulders. The aim is to identify any unwanted defects which may affect pavement performance. The shoulder condition data shall be collected over 100/200 meter intervals as:
Good
Fair
Bad
Failed or non-functional
Side Drainage Condition The drainage condition shall be recorded as per the requisite IQL for both the left and right hand side drains. The aim is to identify any drainage problems which may affect pavement performance. The drainage condition data shall be collected over 100/200 meter intervals as:
Good
Fair
Bad
Failed or non-functional
It should be noted that this pertains to the ability of the drains to function for their intended purpose.
3.6 Pavement StructureYes
Assessment of the pavement structural characteristics is one of the most important data items for monitoring the pavement deterioration. The strength and composition provide an indication of the type of remedial measures required such as maintenance and repair/ rehabilitation. Non-destructive tests (NDT) are the preferred method to determine the pavement strength characteristics as the pavement structure and its integrity is not disturbed.
Static, steady state, and impulse loading tests are available to measure pavement deflection from which pavement strength is determined. Impulse loading is the preferred method as it simulates the dynamic load on the pavement structure.
As an outcome of the pavement testing the Client may require the DCC to calculate modified structural number SNC according to the World Bank publications.
Pavement Deflection The pavement deflection bowl shape is to be measured as the deflection or rebound deflection under a certain pre-determined load using an automated method of measurement. It will be measured using Non Destructive Test (NDT) methods such as Falling Weight Deflectometer (FWD) or Benkelman Beam Deflection (BBD) . The minimum sampling interval will be 200/500 meter staggered interval.Falling Weight Deflectometer The deflection measurements shall be taken by the Falling Weight Deflectometer following the Austroads Test Method AG:AM/T006: Pavement Deflection Measurement with a Falling Weight Deflectomter (FWD).Unless otherwise specified a target stress of 566Kpa (corresponding with a load of 40KN) shall be used. Actual test loads must be within 10% of the target load level. The sensors spacing shall be kept at 0, 200, 300, 450, 600, 900 and 1500 mm / 0, 200, 300, 450, 600, 750, 900, 1200 and 1500 mm measured from the centre of the applied load. The load pulse shall be applied through a loading plate of diameter of 300 mm. The loading plate shall have a rubber pad of at least 5 mm thickness.The operator must follow the manufacturers instructions for use of the equipment. The test locations shall be cleaned of loose stones and debris to ensure that the loading plate and deflection sensors are properly seated. Lower the loading plate and the sensors and ensure they are resting on a firm and stable surface. Raise the loading weights to the appropriate height to generate the target load level, and drop the weight. Record the peak load and resulting peak surface deflections. Perform two additional load sequences and compare the results of second and third sequences. If the difference is greater than 5% or 5 micron for any sensor, note the variability in the report. The peak load, temperature and deflection sensor readings resulting from the third drop load constitute the test results. The pavement surface and ambient temperature shall be measured at each test location. The factors affecting the test results shall be recorded in the field. These include but not limited to deviation from the test lane, surrounding structures (culvert/bridge) and localized surface contamination etc.
Benkelman Beam Deflection
The rebound deflection shall be measured using a truck or trailer with an axle load of 8.20 0.15 tonnes equally distributed on two dual tyred wheels operating at the inflation pressure necessary to give a tyre contact area of 0.048 0.0002 m2. The tyres shall preferably be 10.00 x 20, 12 ply with tubes and rib treads.
The test points shall be located at 0.7 m from the edge of the pavement/lane. The truck shall initially be positioned with the test wheel between 100 and 150 mm to the rear of the test spot. The probe of the beam shall be inserted between the dual tyres of the test wheel with the toe located on the test spot. The locking device shall be released and the rear of the beam adjusted so that the plunger is in contact with the dial gauge. The dial gauge shall be set to read between 9 and 11 mm (the actual reading need not be recorded) and the vibrator set in operation. The truck shall be moved forward at creep speed so that the test wheel passes over the test spot and continues advancing to 2.7 0.1 meters beyond the test spot. The starting, intermediate and final readings shall be recorded.
The tyre pressure shall be checked before the first test and then at intervals not exceeding three hours. Temperature measurements shall be made 40 mm below the pavement surface. The pavement rebound deflection at the standard temperature of 200C shall be calculated and reported.
Layer Modulus The DCC shall determine the elastic modulus of the different pavement layers and subgrade using the measured deflection basin and pavement composition. The proposed has to be elaborated by the DCC in the technical proposal.
Pavement Composition Non Destructive Method Pavement layers thicknesses are to be measured using a non-destructive testing method such as Ground Penetrating Radar (GPR) or equivalent. As a minimum, the data shall be provided at the same sample points as the deflection basin measurements or 200/500 meter staggered interval. Optionally, in addition to offering point measurement, the DCC may offer continuous measurements. Should continuous measurements be made, the data will need to be extracted from the continuous measurement locations to the deflection basin measurements or 200/500 meter staggered interval.
The data shall consist of the thickness expressed in cm, of asphalt, base and sub-base and/or improved subgrade (if distinguishable).Pavement Composition Destructive Method Dynamic Cone Penetration (DCP) testing shall be carried out, to a depth ranging from 700 mm to 1000 mm below the surface, with intervals determined based on the materials used in the construction and the soil condition.
In general, DCP tests will provide valuable data regarding the thickness of the pavement's unbound layers and, under suitable conditions, will give an indication of their strength. It is considered essential that the tests should be made in the wheelpaths. The asphalt layer shall be removed with a core drilling machine or manually first, to avoid damage to the cone and the danger of obtaining a misleading result.DCP test shall be carried out at 1/5 Km interval.
3.7 Traffic CountingYes
Traffic is most neglected item though one of the critical parameters for the maintenance planning. Enough quality assurance must be emphasized for capturing the traffic data as accurate as possible. The type of traffic counting shall be carefully chosen considering the prevailing traffic on the road network and its intended use. For example manual methods can capture all modes including pedestrian traffic if required where as automated traffic counting can capture certain modes. However, automated method can provide more accurate data compared to manual method.
The traffic counting shall be conducted using manual/automated traffic counting equipment . The classified traffic volume count shall be carried out for 3/5/7 days 12/24 hours continuous and direction-wise at the selected survey stations. The vehicle classification system shall be discussed with Client before the survey starts. As guidance the classification shall be in line with the FHWA/HDM-4 classification.
The survey locations shall be discussed and agreed with Client before the surveys commence. The locations shall be as close as possible to the regular traffic counting stations. The data shall be provided in electronic format suitable to Client agency irrespective of the type of counting. The data shall be analyzed and at least the following shall be submitted:
Daily and direction wise traffic;
Daily traffic volume including classification; Average Daily Traffic (ADT);
Annual Average Daily Traffic (AADT) Client shall provide the seasonal factors.
Manual Traffic Counting The traffic counting shall be carried out by survey enumerators by entering the traffic in a pre-defined format. The survey site shall be appropriately designated and marked such that it provides survey enumerators a safe place for the duration of the counting. DCC shall exercise appropriate QA procedures for providing quality data. At their own discretion Client shall choose to undertake a parallel and independent traffic classification survey for 1/3 hours to compare with the data collected by DCC. The DCC shall repeat the traffic surveys for the specified period in case the data is rejected by the Client. Client shall provide enough evidence for the rejection.Automated Traffic Counting Traffic volume shall be captured using a portable type, battery-operated, multi-lane time interval traffic counter and classifier . The equipment shall be capable of collecting valuable traffic data, primarily vehicle count and classification. The other data that can be captured are gap, headway, speed by axle and speed by length.
The Automated Traffic Count and Classifier (ATCC) shall be of a modular design, flexible configuration, high performance cross-talk free digital loop detector, advanced axle sensor performance tracking, comprehensive system performance monitoring, detail sensor diagnostics capability, user-friendly set-up and complete diagnostics, full range of classification algorithms, provision for industry standard data formats, user-modifiable parameter sets, comprehensive software support. Data from ATCC shall be able to download onto Laptop, PC, Datahog, or remotely with a telephone modem.
3.8 Right of Way VideoYes
Video provides a permanent record of the right of way.
Right of Way VideoThe visible right-of-way (ROW) is to be directly digitized and stored at 800 x 600 pixel or better. The data may be collected as either continuous or on a time or frame based system, preference will be given to continuous data. Location identification information must be superimposed on each frame and a playback system which facilitates easy review and location of specific road sections must be included.
3.9 Digital PhotographsYes
Digital images provide a permanent record. These can be used to locate the LRPs or nodes in the future in the event they go missing.
Digital Images of LRPs/Nodes Each Node and LRP shall have at least one digital image recorded for it. This shall show sufficient information to allow reinstatement of the LRP or node. The photo names shall be stored in a file, and include geo-coordinates to allow the images to be accessible via hyperlinks in a GIS .
Digital Images of Bridges Each Bridge shall have at least one digital image recorded for it. The photo names shall be stored in a file along with geo-coordinates to allow the images to be accessible via hyperlinks in a GIS .
3.10 Cross Drainage StructuresYes
Very basic data should be included as part of the pavement condition surveys. The detailed inventory and condition assessment of cross drainage structures is beyond the scope of this TOR.
Location of Structures Major structures such as bridges shall be inventoried as per the specified IQL or as otherwise directed by the Client, but in not more detail than IQL-3.
Predetermined categories may be established and agreed with the Client for inventory and condition purposes. The existing bridge identification system shall be utilized unless otherwise agreed with the Client.
Overall Condition The overall condition as a single parameter of the bridges shall be recorded as agreed with the Client. The DCC is encouraged to describe their methodology of the condition to be collected.
4 CALIBRATION AND VALIDATION
The terminology for calibration and validation should be clearly specified in the tender document. For the purposes of the contract the following definitions must be used:
Calibration refers to the process of determining the relation between the output (or response) of a measuring instrument and the value of the input quantity or attribute, a measurement standard. Calibration refers to the instrument or components of the system that has to measure to a given standard. For example the calibration certificate would be a factory or industry standard for a given device such as a distance meter. The purpose of the validation is to confirm the proposed methodology, the data collection, data processing, and reporting processes meet the required standard, while maintaining consistency between different data collection equipment. The validation process therefore test the system as a whole including the operator. During validation it is confirmed that the measurements are accurate, repeatable and reproducible. Furthermore, it also demonstrates that the equipment proposed by the DCC can operate under the expected conditions of the network. Therefore in addition to meeting the data specification detailed above, all equipment must also meet the validation requirements detailed below. Both calibration and validation needs to be specified by the contract.Calibration of the equipment confirms that measurements can achieve a measurable/specified tolerance. Calibration does not confirm that the equipment can measure the required parameter from a moving vehicle. Data is filtered and processed to achieve the desired output. The DCC must provide relevant certificates to fulfil this requirement.
Validation demonstrates that the survey equipment can be operated by the DCC on roads that are characteristic of the Clients particular network, and provide meaningful data of sufficient accuracy to meet its intended use. The results from the validation process are approved by the Client.
4.1 Calibration Methodology Yes
Calibration by correlation with other vehicle mounted survey equipment should not be used. All measuring equipment must have calibration certification to an international standard.
Calibration certification will confirm individual equipment accuracy as defined above for the measuring components of the system, the accelerometers the lasers and the distance measuring system etc.
When equipment is replaced at any stage of the contract it must undergo a calibration process as per the start of the contract.
4.2 Validation MethodologyYes
Validation of equipment needs to happen at three stages:
Prior to the survey the Client or the Client Representative needs to approve the DCCs validation results to be according to the contractual requirements;
Most of the equipment manufacturers specified minimum daily calibration/validation procedures. The DCC must nominate, in the Quality Plan, the process of continues calibration and validation processes that are undertaken during the surveys. Any outputs/data from these processes must also be provided to the client;
It is good practice also to specify a post survey validation process which is exactly the same as the validation prior to the survey commencement. The post validation survey is recommended for larger networks (say more than 5,000KM).
Validation should be recognized as separate processes within the overall objective of obtaining accurate and reproducible roadway profilers.
A validation program should be carried out prior to acceptance of the equipment and /or before the start of data collection activities.
Continued measurement validation must be carried out during and at the completion of data collection activities.
A minimum of 6 sites, each 300 meter long, should be used for roughness, and 5 sites each 200 meter long for both texture and rut depth, selected to reflect the full range of operating conditions likely to be encountered in the surveys.
A post survey validation should be carried out on completion of the overall survey When equipment is replaced at any stage of the contract it must undergo a validation process as per the start of the contract.
Validation ApproachThe survey equipment must be validated at each site against a reference measurement. This is done by measuring sections of roads with the reference instrument, and then the same sections with the survey equipment.
For roughness calibration equipment must be compatible with ASTM standard E950 (2004) Standard Test Method for Measuring the Longitudinal Profile of travelled Surfaces with an Accelerometer Established Inertial Profiling Reference, Class I.
The survey equipment must make at least five repeat runs over each of the validation sections at 4 nominal speeds of 25, 50, 75, and 100 km/hour or within the limits specified by the manufacturer. The results must be averaged to give the profile at each of the nominated speeds.
The line of best fit between the reference measurement and the survey equipment using least squares regression is then established:
RM = SE x A + B
Where:
RM = The measurement from the reference equipment
SE = The measurement the survey equipment
A = slope of line of best fit
B = intercept of line of best fit (regression offset)
The equipment is considered validated when A and B, and R2 (the coefficient of determination) are within the specified parameter ranges detailed in Table 1 below for all sites combined.
Repeatability this is the expected standard deviation of measurements obtained in repeat tests, using the same survey equipment on a single randomly selected road. The standard deviation of measurement on each segment must be within the tolerance defined for the different surface types from the mean for each of the 5 repeat runs.
Assuming a normal distribution then the 95% confidence intervals for the roughness is given by.
Where:
data = the data measured by the instrument (eg IRI m/km, mm rut depth, etc.)
s = the standard deviation of the data in the same measurement units
n = the number of runs
t = 2.776. This is the critical value for the t Distribution for a Critical t Confidence Interval of 95%, see Modern Data Analysis - A First Course in Applied Statistics, Hamilton LC, 1990. The equipment is considered to be repeatable when it is within the specified percentage of the mean, refer Table 1 below.
Table 1: Validation Limits
ParameterSlope
(A)Intercept
(B)Correlation
R2Acceptance Limit
Roughness0.981.020.05IRI0.991.00< 0.030 IRI
Response Type Roughness Not Applicable0.5IRI0.931.00< 0.30 IRI
Rutting0.981.020.2mm0.971.000< 0.050 RD
Texture0.981.020.05mm0.981.000< 0.030 MPD
4.3 RoughnessYes
Setting Reference Profile The base road surface profile over the validation sections must be measured using a reference Class 1 profiler. The reference profiler is used to record the profile of each wheelpath over the full validation length. Each wheelpath must be measured at least three times. The reference profile must be taken as the average of the individual readings measured in each wheelpath.
Spectral Density - The ability of the survey equipment to measure the broad range of wavelengths that constitute the roads longitudinal profile can be demonstrated through the equipments frequency response or transfer function characteristics. It is therefore recommended that the spectral density be measured and plotted along with the reference site spectral density measured. This is not applicable for response type roughness measuring systems.
Interrupted Data Collection interrupted data must be validated by:
driving over the validation sections at varying speeds during each run and achieving the same repeatability when compared to the constant speed run. demonstrating the effects of stop and go and the effectiveness of the equipment for handling survey interruptions (slow traffic etc).Autospectral density functions can be determined using the Road Ruf Public Domain Software. This software is available at the UMTRI Road Roughness User Site at http://www.umich.edu/erd/roughness/
Examples of reference profilers are the ARRB TR Walking Profiler, the Face Dipstick, the ROMDAS Z-250.
A comparison of the spectral density of the survey profiler and the reference profiler is used to demonstrate that the profiler can measure the range of wavelengths that constitute the roads longitudinal profile. Ideally the two should be identical.
4.4 RuttingYes
The transverse profile and rutting validation process is undertaken on sections that are representative of the network and covering the full range of rutting expected on the survey network. The sections chosen must as a minimum cover a range of rut depths in both left and right wheelpaths up to 40 mm.
The validation of the reference profile is the preferred method of validation, however, this either requires specialized equipment or is very time consuming. Most validations are therefore done by measuring the rut depth with a straight-edge and wedge and comparing the surveyed rut depth with that from the measurement system.
Rut Depth - Is defined as the height between the pavement and a user defined straight edge placed across the rut, i.e. the distance obtained from the manual straight edge and wedge method.
Measurement Location Profile and/or Rut Depth measurements are taken at 5 m intervals along each 200 m section.
Using Reference Profiles Setting Reference Profile The reference transverse profile on each of the validation sections must be measured using either a reference profile beam or surveyor rod and level or other approved method. The method adopted must be capable of measuring the transverse profile at 100 mm intervals to a vertical accuracy of 0.25 mm. Reference Profile Validation - Transverse Profile graphs for both the reference profile and the survey equipment for each speed must be provided to demonstrate that the equipment is measuring the true pavement transverse profile.Using Straight-Edge and Wedge Establishing the Reference Rut Depth The rut depth on each of the validation sections is measured in both left and right wheel paths to an accuracy of 0.5 mm at 5 m intervals along each 200 m section.
Rut Depth Validation The survey equipment must be validated at each site against the reference rut depth derived from the straight edge and wedge or, where a reference profile beam is used, from the rut depth calculated from the reference profile.
A visual review of the reference and survey profiler transverse profiles is the easiest way to confirm that the survey profiler is able to define the pavement transverse profile.
4.5 TextureYes
The validation of texture depth is often impossible due to the absence of available equipment for using in the validation process.
The texture validation process is undertaken on pavement sections that are representative of the survey network. The range of Texture Depth required for this validation should be determined from the characteristics of the n
