This report presents the work completed for the research study Safety Benefit Evaluation of a Forward Collision Warning System (FCW) under Contract DTNH22-05-D-01019, Task Order # 13. The purpose of this study was to estimate the safety benefits that may be obtained by deploying an FCW system in heavy vehicles. The approach involved simulating driver collision avoidance behaviour, with and without FCW alarms, in response to rear-end (RE) conflicts recorded in a previous naturalistic driving study. The naturalistic driving dataset used was produced by a heavy-vehicle field operational test (FOT) that was conducted by the Virginia Tech Transportation Institute (VTTI). RE conflicts were identified using methods that were based on Volvo’s Intelligent Vehicle Initiative Field Operation Test (Volvo, 2005), which observed heavy vehicles operating with an FCW system for one year. The algorithms used by the Eaton VORAD (Vehicle On-Board Radar) FCW system were applied to the identified RE conflict data. The auditory alarm severity and timing of the FCW alarms (that would have occurred had an FCW system been installed) were computed. Drivers' actual alarm perception-response times and braking-levels that were measured during the Volvo (2005) FOT were then used to simulate driver response behaviour to the theoretical FCW alarms using a Monte Carlo approach. An assumption was made that drivers made the best decision when receiving FCW alarms, allowing them to apply the brakes sooner and possibly avoid a crash. Enhancing the approach used in Battelle (2006), the number of conflicts avoided, as well as the additional response time available prior to encountering a crash, were both used to compute a prevention ration (PR) and exposure ratio (ER). The PR and ER were then combined to compute an overall crash reduction estimate. This simulation deter-mined that a nationwide deployment of FCW systems in heavy vehicles could reduce the number of RE crashes by 21 percent (p < 0.001). (Author/publisher)
Abstract