Examining Injury Severity of Not-At-Fault Drivers in Two-Vehicle Crashes

The focus of this paper is to examine the injury severity of not-at-fault drivers in two-vehicle crashes. North Carolina crash data collected from 2009 to 2013 were used for the analysis. Ordered probit model was initially chosen because of the ordinal nature of the dependent variable (injury severity of the driver not at fault). However. the data failed to obey the proportional odds assumption accompanied with the ordered probit model. Therefore, a partial proportional model was fitted for two-vehicle crashes. Compared with the physical condition of at-fault drivers, the physical condition of not-at-fault drivers had a greater effect on the severity of injury to the not-at-fault drivers. Exceeding the speed limit, aggressive or reckless driving, and going the wrong way are the three traffic rule violations of at-fault drivers that are more likely to result in severe injuries to not-at-fault drivers than disregarding traffic signs. signals, and markings. Similarly, a crash involving an at-fault driver with violations of two and three traffic rules is 1.68 and 2.86 times likely to result in severe injuries to not-at-fault drivers compared with a crash involving an at-fault driver with only one traffic rule violation. Motorcyclists are observed to be highest risk with the odds of severe injury to motorcyclists who are not at fault. Crashes with female at-fault drivers are less likely to result in severe injury to the not-at-fault drivers. Female drivers are also more likely to be severely injured when they are not at fault.