California Partners for Advanced Transportation Technology

This report describes the SafeTrip-21, Networked Traveler Foresighted Driving Field Experiment conducted as part of the US DOT’s SafeTrip-21 initiative. This experiment developed and evaluated an Advanced Driver Assistance System providing soft-safety or situational awareness alerts regarding “Slow Traffic Ahead” when driving on a freeway. The Networked Traveler system detects slow traffic or queues at several thousand locations in the Bay area, monitors the locations and speeds of its test subjects as they drive, and determines if the driver is approaching the slow traffic fast enough to warrant an alert. If so, the system alerts the driver through an auditory interface. The desired outcome is a foresighted reduction in speed, resulting in a smoother overall transition into the oncoming traffic queue. The system aims to reduce the likelihood of end-of-queue crashes on freeways, this being a subset of the class of rear-end crashes. The hypothesis is tested by computing measures representing the Root Mean Square (RMS) Error of Speed, Peak Deceleration Rate, Mean Deceleration Rate, Deceleration Due to Braking, Pre-Braking Deceleration, and Time before the start of braking. Amongst these, the RMS Error of Speed across all subjects most clearly confirms the test hypothesis -enhanced situational awareness results in smoother driving.