Visual Performance and Safety Benefits of Adaptive Curve Headlighting Systems

Very few data have been published that demonstrate the possible benefits to safety from advanced headlighting technologies on nighttime driving safety. By comparing insurance claim information for different vehicle models equipped with such systems, the Highway Loss Data Institute (HLDI) compared vehicles with and without adaptive curve lighting (ACL) systems. Overall, the HLDI data are consistent with a safety benefit when these systems are used, as defined by reductions in property damage and injury claim frequencies. Injury claim frequency reductions were larger than those in property damage claims. To help interpret the HLDI findings, visual performance analyses were conducted based on prior studies of ACL for curves varying in radius. Reaction times using conventional headlights and ACL systems and light levels at oncoming drivers' eyes from vehicles with and without ACL systems were used to estimate the potential benefits of these systems on visibility as well as to estimate disability glare impacts to other drivers. The average improvements in RVP for these combined scenarios associated with ACL systems were compared to a previously published transfer function relating visual performance and nighttime crash reductions associated with lighting. The correspondence between overall visibility improvements and nighttime crash reductions can provide a rational foundation for predicting the potential safety benefits of adaptive vehicle headlighting systems.