Driver Workload at Higher Speeds

The goal of this Texas Department of Transportation project was to gain a better understanding of driver performance at high speeds. Specific efforts included the following studies: (1) The Closed-Course Pilot Study consisted of observing and recording the activities and actions of a series of drivers following a lead vehicle going either 60 or 85 mph. (2) The Open-Road Pilot Study recorded participants driving between Odessa and Pecos, Texas, within 70- and 80-mph sections. (3) The Simulator Pilot Study determined driver reactions to a looming vehicle (both passenger car and large truck) and also generated directions for how to conduct the Phase II simulator study. (4) The Simulator Phase II Study collected brake reaction to a vehicle looming in the driver’s view for 50 participants. Conditions varied included initial speed, lead vehicle type, lead vehicle deceleration rate, and workload level. (5) The Following Distance Study used data from traffic counters to identify speed and axle gap data on freeways with 60-, 70-, and 80-mph posted speed limits. (6) The Gaps at Passing Study measured gaps during passing maneuvers for daylight conditions on freeway sections. When responding to a vehicle slowing in their lane, drivers in the Simulator Phase II Study at the 85-mph speed had a reaction time that was statistically longer than that of drivers at the 60-mph speed. In the simulator, on-road, and test track studies where researchers directly measured driver performance, performance declined when a driver was multitasking at the higher speed. The traffic counter data showed that axle clearance distance was larger for the 80-mph freeway sites as compared to the 60- and 70-mph speed limit sites, both statistically and practically. The Gaps at Passing Study found a different result; drivers used similar passing gap distances on both 70- and 80-mph sections.

  • Record URL:
  • Supplemental Notes:
    • Project Title: Driver Workload and Visual Studies. Report Date: September 2009; Published: February 2010.
  • Corporate Authors:

    Texas Transportation Institute

    Texas A&M University System, 3135 TAMU
    College Station, TX  United States  77843-3135

    Texas Department of Transportation

    Research and Technology Implementation Office, P.O. Box 5080
    Austin, TX  United States  78763-5080

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Fitzpatrick, Kay
    • Chrysler, Susan
    • Park, Eun Sug
    • Nelson, Alicia A
    • Robertson, James
    • Iragavarapu, Vichika
  • Publication Date: 2010-2


  • English

Media Info

  • Media Type: Web
  • Edition: Technical Report
  • Features: Figures; Photos; References; Tables;
  • Pagination: 214p

Subject/Index Terms

Filing Info

  • Accession Number: 01154211
  • Record Type: Publication
  • Report/Paper Numbers: FHWA/TX-10/0-5911-1, Report 0-5911-1
  • Contract Numbers: Project 0-5911
  • Created Date: Apr 9 2010 11:14AM