Examining Optimal Sight Distances at Rural Intersections - MnDOT & LRRB

Principal Investigator(s):

Nichole Morris, HFSL Director, Mechanical Engineering

Project summary:

Decisions made regarding driver sight distance at rural intersections are complex and require considerations for safety, efficiency, and environmental factors. Sight distance, cross-traffic velocity, and vehicle placements significantly affect driver judgment and behavior at these intersections. Results from a simulation study demonstrated that longer sight distances of 1000 feet and slower crossing speeds (i.e., 55 mph) were more accommodating for participants attempting to select gaps and cross from the minor road, corresponding with (1) lower mental workload, perceived risk, difficulty, and anxiousness, and (2) better performance in terms of estimated crash rate, and larger TTCs. Second, longer distances of 1000 feet appear to aid drivers’ responsiveness on the main road approaching an intersection, specifically when another driver on the minor road runs the stop sign. Minor road drivers positioned close to the roadway at the stop sign, compared to standard stop bar placement, tended to help reduce the speed of main road drivers. Overall, results demonstrate a systematic improvement in the performance of both minor and major road drivers with the implementation of a 1000 feet sight distance at rural thru-STOP intersections.

Project details:

  • Project number: 1003325 WO 25
  • Start date: 06/2017
  • Project status: Completed
  • Research area: Transportation Safety and Traffic Flow
  • Topics: Driver Performance and Behavior