Identifying the main factors contributing to driving errors and traffic violations - Results from naturalistic driving data

- Violations committed in the past best predicted current violations.
- Engagement in risky secondary tasks was related to committed violations.
- Drivers used the driving context to decide when to engage in risky behaviors.
- High-risk visually distracting secondary tasks were associated with errors.
- Cognitive distractions did not have a detrimental effect on driving performance.

Researchers have identified various factors that likely affect aberrant driving behaviors and therefore crash risk. However, it remains unclear which of these factors poses the greatest risk for either errors or violations under naturalistic driving conditions. This study investigated important variables contributing to driving errors and traffic violations based on naturalistic driving data from the second Strategic Highway Research Program (SHRP 2). In addition, this study identified factors determining the drivers' willingness to perform common secondary tasks while driving, which have been associated with different degrees of crash risk. Results showed that anger, passenger presence, and persistent individual differences in driver behavior were the main factors associated with committed violations; surprise, high-risk visually distracting secondary tasks, and the driving task demand passing through an interchange were the main factors associated with errors. The willingness to engage in risky secondary tasks while driving appeared to be related to an overall tendency to engage in risky driving behaviors. However, drivers considered the driving context particularly when engaging in visually distracting secondary tasks. This study's comprehensive approach should be a step towards generating a complete model of the variables that contribute to, or mitigate dangers in traffic.