Risk in our midst: Centrelines, perceived risk, and speed choice

• Two experiments compared drivers’ speed choices and ratings of risk in video-based simulation and on-road.
• In high traffic conditions double yellow centrelines were associated with lower speed choices and higher risk ratings.
• Driving on narrow roads was also associated with lower speeds and increased risk ratings.
• There was a high level of consistency in the data obtained from the video simulation and the on-road driving.

The idea that drivers’ perceptions of risk affect their decisions and choices, particularly as regards their speed, is at the heart of many years of our education, engineering, and enforcement strategies to improve road safety. Our previous research has shown that horizontal curvature, road width, vertical curvature and separation from on-coming traffic are principal determinants to perceptions of risk on rural roads. The present study examined the relationship between drivers’ perceptions of risk and the speeds they choose to drive. Participants drove high definition videos of familiar rural roads in a driving simulator and a smaller group of participants drove the same roads in a university fleet vehicle similar to the one used in the simulator. The results showed that double yellow and wide centreline markings were associated with lower speed choices and higher perceptions of risk, an effect magnified under high traffic conditions. Similarly, in both the simulator and on the roads, driving on narrow roads was associated with significantly lower speeds and increased risk ratings, while wider roads showed a small but significant increase in speeds as compared to standard width control roads. Finally, a range of other road and traffic conditions such as one-lane bridges, level crossings, police cars, and crash area warning signs were also found to be associated with lower speed choices and higher risk perceptions.