Fleetwide Safety Benefits of Production Forward Collision and Lane Departure Warning Systems 2014-01-0166
Forward Collision Warning (FCW) and Lane Departure Warning (LDW) systems are two active safety systems that have recently been added to the U.S. New Car Assessment Program (NCAP) evaluation. Vehicles that pass confirmation tests may advertise the presence of FCW and LDW alongside the vehicle's star safety rating derived from crash tests. This paper predicts the number of crashes and injured drivers that could be prevented if all vehicles in the U.S. fleet were equipped with production FCW and/or LDW systems. Models of each system were developed using the test track data collected for 16 FCW and 10 LDW systems by the NCAP confirmation tests. These models were used in existing fleetwide benefits models developed for FCW and LDW.
The 16 FCW systems evaluated could have potentially prevented between 9% and 53% of all rear-end collisions and prevented between 19% and 60% of injured (MAIS2+) drivers. Earlier warning times prevented more warnings and injuries. The lower operating speed thresholds of some systems also greatly affected benefits estimates. The results of this study suggest that future FCW testing protocols should also include low-speed warnings under 25 mph because of the potential safety benefits of these systems.
For LDW systems, the 10 systems tested had similar benefits if distance to the lane marking was used as the metric for delivering the warning. For all vehicles, the number of crashes prevented varied from 29% to 32% and the number of injured (MAIS3+) drivers prevented varied from 25% to 27%. LDW benefits are more sensitive to Time to Lane Cross (TTLC) as a metric for warning delivery. The number of crashes varied from 13% to 47% and the number of injured drivers varied from 10% to 42% when TTLC was the metric used to deliver the LDW. This result suggests that future LDW tests should consider TTLC as a metric in addition to distance to lane cross.