Evaluating the Influence of Stop Line Position on Driver Stopping Distances at Rural, Stop-Controlled Intersections

Rural, two-way, stop-controlled intersections represent a high risk for serious injury and fatality owing to the increased propensity for right-angle crashes following stop sign running or poor gap acceptance by drivers on minor roads. Safety countermeasures are often aimed at improving minor road stop sign compliance, gap selection, sight distance, and major road speeds. Stop lines have been found to increase intersection recognition and indicate stopping position. A simulation study of licensed drivers (n = 50) examined stopping behaviors at a random series of two-lane, two-way, stop-controlled intersections with no stop line, a stop line 1.22-m back from the lane edge, or 9.14-m back from the intersection edge. Participants experienced each stop line type twice. Stopping distances were observed at two slow speed/stopping thresholds: <2.0 m/s and 0.0 m/s. Of the three conditions, participants stopped closest to the intersection with the 1.22 m stop line and furthest from the intersection with no stop line. At both stopping speed thresholds, differences in stopping distances were statistically significant between the 1.22 m stop line and the 9.14 m stop line, the 1.22 m stop line and no stop line, and between the 9.14 m stop line and no stop line. Order and first/last stopping distance differences were nonsignificant. The results suggest that stop lines may perceptually anchor drivers to stop closer to intersections and may help increase sight distances, improve gap acceptance, and slow mainline driver speeds.