The National Academies

NCHRP 07-16 [Final]

Recommended Revisions to the AASHTO Guidelines for Traffic Data Programs

  Project Data
Funds: $350,000
Research Agency: Cambridge Systematics, Inc.
Principal Investigator: Anita Vandervalk
Effective Date: 3/29/2005
Completion Date: 3/28/2007


Data on traffic volumes and vehicle classifications, weights, speeds, and lengths are key elements in many aspects of transportation system planning; apportionment of Federal-aid; freight planning; urban and statewide modeling; design and management of pavements and bridges; and safety, economic, and environmental analyses. These data are also integral to information shared with travelers and used in calculating performance measures related to congestion and travel time, reliability, and predictability.

The AASHTO Guidelines for Traffic Data Programs was published in 1992. Since that time there have been significant changes in the following:
  • Technologies and tools available for collecting, managing, and reporting data from traditional state traffic data programs; ITS traffic monitoring; and MPO and other local agency monitoring programs.
  • Acceptance and validation of methodologies for archiving traffic data, factoring short duration counts for seasonal adjustments, and imputing missing data.
  • Uses of traffic data for pavement and bridge design; apportionment formulae for Federal-Aid funding; development of performance measures for indicators such as travel time predictability and reliability; and freight, security, and safety planning.
  • New transportation and environmental planning and modeling requirements.
  • Application of data for GIS, Internet availability, and other electronic data sharing tools.

Updated guidelines will assist the many transportation agencies that rely on traffic data to monitor, manage, and operate highway systems; forecast improvement needs; and determine priorities for investment. In addition, updated guidelines will provide assistance to states in meeting federal requirements for traffic monitoring systems.


The objective of this research is to develop recommended revisions and enhancements to the AASHTO Guidelines for Traffic Data Programs. It will be necessary for the research to identify and describe the success factors and best practices for establishing and maintaining effective traffic data programs. This will focus on new technologies, applications, methodologies, and requirements to increase the utility of traffic data to meet expanding user needs for high-quality, reliable, and representative information. 

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