Does talking with a fellow passenger affect everybody the same? An impact assessment on driving performance and behavior

Driver distraction is indicated as one of the most significant causes of road accidents. In literature, among the internal factors causing distraction, the in-vehicle passenger or remote conversation, seems to affect significantly driving performance and behavior, and the relevant measurements on representative variables such as reaction time, speed, deceleration reactions, time-to-collision and distance from the centerline. This paper aims at investigating the impact of conversing with a fellow passenger on driving performance depending on the level of conversation, the driver characteristics and the driving conditions. For this purpose, a driving simulator experiment was carried out, in which 42 male and female participants were asked to talk with a fellow passenger while driving on a mountainous rural road during daytime. Driving performance was assessed through three variables, reaction time, speed and distance from the centerline, as affected by drivers' age, gender and driving experience, under three conversation scenarios: "no conversation", "simple conversation" and "complex conversation". Results showed that reaction time, speed and distance from the centerline are significantly affected by conversation, with speed being indicated as the variable mostly affected compared to the other two variables. Regarding drivers' characteristics, it was indicated that reaction time is significantly affected by age and driving experience, speed is affected by age, gender and driving experience, and, distance from the centerline is affected by age