Car crashes: The effect of passenger presence and other factors on driver outcome.

This study was conducted to evaluate whether the presence of passengers affects the consequences, for drivers, of road crashes, also taking into account other factors associated with driver outcome following a crash. Data on car drivers involved in accidents occurring in 2004 and 2005 in the Italian province of Pavia were analysed. The data came from the Pavia office of the Italian Driver and Vehicle Licensing Authority and are based on police accident reports. Logistic regression analyses were performed. Injury risk in drivers under 25 years of age increased in the presence of a passenger. This effect was not found in drivers aged 25 years and older. In single-vehicle accidents, passenger presence was found to exert a negative effect among the young drivers, but a positive one among the adult drivers. Crash outcome for young drivers is more likely to be severe when the passenger is male. This study confirmed the existence of other risk factors influencing the severity of crashes for drivers: gender, penalty points, possession of other driving licences in addition to the basic car one, time and day of the week on which the crash occurred, dynamics and place of the crash. These results underline the importance of evaluating passenger presence as a factor influencing crash outcome. Further studies assessing the influence of passengers on the risk of occurrence of crashes, and also considering the impact of crashes on passengers and other road users, would improve our understanding of this topic.