The interaction of person and situation within the driving environment: Daily hassles, traffic congestion, driver stress, aggression, vengeance and past performance

Driving safety research has traditionally focused on accident data as a representation of driving performance, but has been limited by inconsistent operationalization and a failure to control for accidents caused by situational or third party factors. The present study demonstrated that the use of single performance measures can provide misleading information concerning driving performance. Specifically, those that involve official reports, those that are a function of personal responsibility, and those with no reference to responsibility were all predicted by unique factors. Further, the present study attempted to clarify the distinction between mild driver aggression and violence. Mild aggression was linked to violence through the tendency toward other dangerous and risky driving behaviours. Specifically, driver violence was most common among aggressive drivers, who also reported having received extremely high levels of demerit points. Mild aggression and violence were also linked to driving vengeance, which has been defined as the infliction of harm in response to perceived injustice from other drivers. Elevated driver aggression was found among vengeful drivers, but, again, violence was most common among vengeful drivers who also reported extreme levels of willful traffic violations. Driver violence appears to represent an extreme behaviour category, which is most common among a small minority of drivers who demonstrate a general tendency toward dangerous driving practices. Finally, in order to evaluate the potential influence of the driving situation on driver stress and aggression, a second study was conducted in which drivers were interviewed in actual driving conditions. Study 2 demonstrated that the consideration of both personal and situational factors provide greater accuracy in predicting both driver stress and mild driver aggression. In high congestion, state driver stress was greatest among high "trait" stress disposition drivers, especially those under the added influence of elevated daily hassles. Stress varied as a function of the situation (congestion), personal dispositions (trait stress), and nondriving factors (hassles). Similarly, in high congestion, driver aggression was linked to driving vengeance and a trait driver stress disposition. Future research must continue to build on interactive research in order to provide a more comprehensive understanding of the driving process.