Measuring and Predicting the Performance of Automobile Traffic on Urban Streets

The National Cooperative Highway Research Program (NCHRP) Project 3-70, Multimodal Level of Service Analysis for Urban Streets, is examining the attributes of the facility that influence travelers' perception of their trips. Many candidate attributes have been identified for each mode of travel, including ones related to the design, operation, and maintenance of the street. For the automobile mode, operational attributes being investigated include average speed, number of stops, total delay, and queue length. Work is underway now to assess the importance of each of the attributes to travelers. Transportation agencies typically operate traffic signal systems to minimize some combination of delay, stops, and queues. Directly measuring the performance of the system in real time has not been practical, but recent advances in detector and controller technologies now make it conceivable. Real-time knowledge of system performance should enable transportation agencies to improve their capabilities in several real-time applications (e.g., adaptive traffic control, traveler information, incident management, and system performance monitoring). The Highway Capacity Manual (HCM) is commonly used for planning and designing urban streets, and travel speed is used to determine the level of service for automobiles. Although the results of NCHRP Project 3-70 may change that, travel speed will probably continue to play a large role. The HCM procedure for predicting travel speeds has weaknesses, particularly in the determination of the free-flow speed and failure to fully account for some factors that influence travel speed, including arterial traffic volume, signal offset, access point density, cross-section design, arterial weaving, and platoon dispersion. This research project uses the HCM term "urban street" although it is expected that the research results will be applicable to a broad range of interrupted-flow arterial and collector roads in urban, suburban, and rural settings. This research has two equally important objectives: (A) development of techniques to measure the performance of automobile traffic on urban streets for real-time applications and (B) development of procedures to predict the performance of automobile traffic on urban streets that will provide a foundation for an update of the HCM.

• Record URL:
  http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=835

Language

• English

Project

• Status: Completed
• Funding: $625000.00
• Contract Numbers:

  Project 3-79

• Sponsor Organizations:

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590

  American Association of State Highway & Transportation Officials (AASHTO)

  444 North Capitol Street, NW, Suite 225
  Washington, DC  United States  20001

  National Cooperative Highway Research Program

  Transportation Research Board
  500 Fifth Street, NW
  Washington, DC  United States  20001
• Project Managers:

  Derr, B

• Performing Organizations:

  Texas A&M Research Foundation, College Station

  Texas A&M University
  College Station, TX  United States  77843
• Principal Investigators:

  Bonneson, James

• Start Date: 20041001
• Expected Completion Date: 0
• Actual Completion Date: 20080131
• Source Data: RiP Project 8982

Subject/Index Terms

• TRT Terms: Arterial highways; Level of service; Queuing; Signalized intersections; Traffic speed; Travel time; Urban areas
• Subject Areas: Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 01548865
• Record Type: Research project
• Source Agency: National Cooperative Highway Research Program
• Contract Numbers: Project 3-79
• Files: RIP
• Created Date: Dec 28 2014 1:00AM