Designing for Target Speed

The American Association of State Highway and Transportation Officials (AASHTO) defines design speed as “a selected speed used to determine the various geometric features of the roadway. The assumed design speed should be a logical one with respect to the topography, anticipated operating speed, the adjacent land use, and the functional classification of the highway.” The working definition for “target speed” is the operating speed that the designer intends for drivers to use. The topic of “design speed” versus “target speed” typically focuses on low-speed urban and suburban roadways, especially where the 85th percentile speed is higher than the posted speed limit. Research is needed to gain a better understanding of how roadway, roadside, and non-roadway elements influence the operating speed—the actual speed of the driver—in order to improve roadway designs and reliably achieve desired speed outcomes. The objectives of this research are to (1) determine the effects of roadway, roadside, and non-roadway elements on operating speeds on roadways with a target speed between 30 and 40 mph and (2) develop recommendations on how the findings can be incorporated into the roadway design process.

• Record URL:
  http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=4765
• Supplemental Notes:
  • To be continued as NCHRP 15-76(01).

Language

• English

Project

• Status: Inactive
• Funding: $750000
• Contract Numbers:

  Project 15-76

• Sponsor Organizations:

  National Cooperative Highway Research Program

  Transportation Research Board
  500 Fifth Street, NW
  Washington, DC  United States  20001

  Federal Highway Administration

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

  American Association of State Highway and Transportation Officials (AASHTO)

  444 North Capitol Street, NW
  Washington, DC  United States  20001
• Project Managers:

  Crichton-Sumners, Camille

• Performing Organizations:

  Texas A&M Transportation Institute (TTI)

  400 Harvey Mitchell Parkway South
  Suite 300
  College Station, TX  United States  77845-4375
• Principal Investigators:

  Brewer, Marcus

• Start Date: 20200729
• Expected Completion Date: 20231229
• Actual Completion Date: 20231229

Subject/Index Terms

• TRT Terms: Geometric design; Highway design; Operating speed; Recommendations; Speed limits
• Subject Areas: Design; Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 01707636
• Record Type: Research project
• Source Agency: Transportation Research Board
• Contract Numbers: Project 15-76
• Files: TRB, RIP
• Created Date: Jun 6 2019 7:49PM