Understanding driver planning behaviour when overtaking a bicyclist: Time to collision estimations from naturalistic driving data

Abstract

In Europe, bicyclist road fatalities have increased for the last ten years. Active safety systems such as Automated Emergency Braking can give a considerable benefit in reducing bicyclist road fatalities, but knowledge on when they should intervene is still limited. Estimation of Time to Collision (TTC) when the driver starts planning to overtake (planning point) could help in improving active safety systems, since TTC is a good estimate of the available mitigation time for the algorithms to intervene. This thesis, carried out using naturalistic driving data from the UDRIVE project, mainly consisted in extracting data from bicyclist overtaking scenarios on rural road and modelling TTC and longitudinal distance to quantify how they are influenced by different factors. The result of the estimation is that the presence of oncoming traffic and an increase in bicyclist lateral distance caused a decrease of both TTC and longitudinal distance at the planning point. Moreover, male drivers showed higher TTC at the planning point than female drivers. Interestingly, the planning point was not affected by the overtaking strategy.