Effects of rearview cameras and rear parking sensors on police-reported backing crashes.

<bold>Objective: </bold>The objective of this study was to examine the effectiveness of rearview cameras, rear parking sensors, and both systems combined in preventing police-reported backing crashes.<bold>Methods: </bold>Negative binomial regression was used to compare rates of police-reported backing crash involvements per insured vehicle year in 22 U.S. states during 2009-2014 between passenger vehicle models with backing technologies and the same vehicle models where the optional systems were not purchased, controlling for other factors affecting crash risk. Rearview cameras were examined from four automakers, rear parking sensors from 2 automakers, and both systems combined from a single automaker.<bold>Results: </bold>Rearview cameras reduced backing crash involvement rates by 17%. Reductions were larger for drivers 70 and older (36%) than for drivers younger than 70 (16%); however, estimates for older and younger drivers did not differ significantly from one another. The Buick Lucerne's rear parking sensor system reduced backing crash involvement rates significantly by 34%, but the reduction for Mercedes-Benz vehicles fit with a sensor system was small and not statistically significant. When averaged between the 2 automakers, effects were significantly larger for drivers 70 and older (38% reduction) than for drivers younger than 70 (1% increase); effects were significant for older but not younger drivers. Backing crash involvement rates were 13% lower among Mercedes-Benz vehicles with a rearview camera and parking sensors than among vehicles without, but this finding was not significant.<bold>Discussion: </bold>Rearview cameras are effective in preventing police-reported backing crashes. Effects of rear parking sensors are less straightforward; it is unclear whether the Buick Lucerne system's benefits are due to the older age of its drivers, characteristics of the vehicle or system, or a combination. Systems may be especially beneficial to older drivers who might have limitations that make backing challenging. Although effect estimates did not differ significantly between older and younger drivers for both system types, the magnitude of the differences was large and the pattern of results was consistent across 6 of the 7 systems examined. When rear visibility systems become required equipment on new passenger vehicles in 2018, rearview cameras can be expected to prevent 1 in 6 backing crashes reported to police that involve equipped vehicles. [ABSTRACT FROM AUTHOR]