Establish Guidelines for Designing Auxiliary Lanes on Frontage Roads

Auxiliary Lanes (ALs) are used on frontage roads to help facilitate safe weaving, merging, and diverging traffic movements to and from the frontage roads at and between freeway ramp terminals. They help balance the traffic load and provide transitions, vehicle storage, acceleration / deceleration to and from driveways, turnaround lanes, and interchange approaches and departures. Acceleration and deceleration lanes, climbing lanes, and right-and left-turn lanes are examples of AL types that can serve different purposes. There is limited guidance for designing ALs on frontage road sat and between freeway ramp terminals. The goal of this project is to identify gaps in existing guidelines and develop design criteria for ALs on frontage roads. To address this goal the research team will: a) review the literature and the state of practice in Texas; b) determine the conditions under which a certain type of AL design improves traffic operations; and c) conduct safety analyses to identify influential factors and develop crash prediction models that practitioners can use to determine how the addition of an AL with certain characteristics can affect safety.


  • English


  • Status: Completed
  • Funding: $330627
  • Contract Numbers:


  • Sponsor Organizations:

    Texas Department of Transportation

    125 E. 11th Street
    Austin, TX  United States  78701-2483

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Managing Organizations:

    Texas Department of Transportation

    125 E. 11th Street
    Austin, TX  United States  78701-2483
  • Project Managers:

    Pridgen, Shelley

  • Performing Organizations:

    Texas A&M Transportation Institute (TTI)

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

    Tsapakis, Ioannis

  • Start Date: 20191201
  • Expected Completion Date: 20221231
  • Actual Completion Date: 20221231
  • Source Data: TxDOT Research Library

Subject/Index Terms

Filing Info

  • Accession Number: 01743946
  • Record Type: Research project
  • Source Agency: Texas Department of Transportation
  • Contract Numbers: 0-7047
  • Files: RIP, STATEDOT
  • Created Date: Jun 24 2020 6:35PM