Leveraging the Second Strategic Highway Research Program Naturalistic Driving Study: Examining Driver Behavior When Entering Rural High-Speed Intersections

163510610174751512017Yang, DavidPDFTech ReportFHWA-HRT-17-016HRDS-30/04-17(WEB)ERural highwaysUnsignalized intersectionsBraking performanceStop signsStopping distancesMotor vehicle driving--ResearchRoads--Interchanges and intersectionsUnited StatesUnited States. Federal Highway Administration. Office of Safety Research and DevelopmentJackson, StevenLeidosUnited States. Federal Highway Administration. Office of Safety Research and DevelopmentTurner-Fairbank Highway Research CenterYang, DavidArnold, MichelleFederal Highway AdministrationOverall, 40 percent of crashes in the United States occur at intersections; a total of 57 percent of fatalities from 1997\u20132004 occurred at stop-controlled intersections, of which 61 percent occurred in rural areas. Factors believed to contribute to these incidents include inadequate surveillance, failure to obey/yield, driver inattention, and speed. This study used naturalistic driving data collected under the second Strategic Highway Research Program to explore drivers\u2019 brake and glance patterns on approach to rural high-speed, stop-controlled intersections from the minor route. Brake distance was found to be sufficiently predicted by brake speed (the speed at which the driver was moving upon initial brake activation). At an average brake speed of 61.7 mi/h, participants first applied the brakes at an average distance of 328.7 ft from the intersection. Older participants (ages 45 to 84) applied the brakes farther upstream, especially at higher speeds, than their younger counterparts (ages 18 to 44). The probability of making a complete stop was found to vary significantly with average annual mileage (AAM) and expressed risk associated with performing rolling stops. Participants with higher AAM were found more likely to make complete stops. Intersection approaches were divided into five 98.4-ft segments, and total glance duration to eight regions of interest (ROIs) within each segment were analyzed. Drivers spent nearly the entire approach glancing to the forward ROI until they were 98.4 ft from the intersection. Between 0 and 98.4 ft, drivers spent an average of 5.1 s scanning the intersecting roadway; a total of 86.5 percent of all intersection scanning occurred in the last 98.4 ft of the approach. A novel difference was found among intersection crossings according to the type of stop performed. Drivers who came to a complete (0 mi/h) stop spent just 39.2 percent of their prestop time scanning the intersection, while rolling stoppers spent 74.5 percent. This suggests that complete stoppers focus on getting to the intersection and then stop, scan, and proceed, whereas rolling stoppers scan the intersection prior to arrival so that they can proceed at higher speeds while maintaining a perception of safety