Measuring the effect of Passengers on the Saftey of Older Drivers

Older drivers cause a disproportionate number of traffic crashes. With the continued increase in the number of older drivers there is significant motivation to further understand the many factors causing these high crash rates. The proposed research will determine whether including or avoiding different passengers groups in the vehicle could improve the safety records of older drivers. One can hypothesize that passengers might represent either a distraction or an advantage (e.g., "extra" helpful eyes on the road and traffic). No significant research on the effect of passengers exists for older drivers. Because the number of teenage passengers in a vehicle has been shown to negatively impact young driver safety in several research studies, limitations on the number of passengers a young driver can carry has become a key component in many state graduated driver licensing systems. In contrast, our previous preliminary research has shown that adult passengers may have a positive effect on older driver safety (padlo et al. 2006). The proposed study will make use of the quasi-induced exposure methodology. The effect of the number, age and gender of passengers on the crash-causing propensity of older drivers will be evaluated. Five years of data from 3 states will be used in the disaggregate analysis; making the results of this research appropriate for potential nationwide countermeasure development.