Which factors are most relevant to drivers’ overtaking choices at two-lane highways: A comparative analysis between questionnaire surveys and driving simulation

Abstract

Overtaking at two-lane highways is a common but risky driving behavior, and various factors may influence drivers' overtaking choices. In this study, we adopted both the questionnaire survey approach and the driving simulation experiment approach to analyze the relative importance of four relevant factors, i.e., the speed of impeding vehicle (IMV), thetypeofimpedingvehicle (IMT), thespeedofopposite vehicle (OPV) and thedistancetooppositevehicle (OPD), and to compare the results of people's subjective judgments and actual operations as well. Based on the data from 313 valid questionnaires (191 males and 122 females) rating these four factors, the importance level of each factor was first ranked by their mean scores. In the simulated driving experiment, a total number of 47 young drivers (28 males and 19 females) completed 356 overtaking scenarios, and the random forest algorithm was used to assess the degree of influence of each factor on drivers' overtaking choices. Afterwards, a post-experiment questionnaire survey regarding the subjective opinion of these four factors was conducted by these 47 drivers, and the Apriori algorithm was used to derive the overall importance ranking of these factors. The results from both the questionnaire surveys and the simulated driving experiments concluded that OPD is relatively the most important influencing factor in drivers’ overtaking choices among the set of four factors considered in this study, which provides road safety analysts with valuable guidance on how to reduce overtaking risk at two-lane highways. However, the main difference appears with respect to IMT, which ranks at the bottom in both questionnaire surveys, but is the second most important factor from the driving simulation, which implies that people's subjective judgments may not completely match their actual operations.