Inter- and intra-driver variability in lane change behaviour

Abstract

Lane change manoeuvres are known to vary widely in lane change duration. This is thought to be an effect of the surrounding vehicles and personal preference of drivers. However, little is known about the effect on steering behaviour during a lane change manoeuvre. Moreover, the relation of the effect of traffic to inter- and intra-driver variability is unknown. This study focuses on quantifying inter- and intra-driver variability in lane change duration and steering behaviour during lane changes in two different traffic scenarios. In an exploratory study, 21 participants drove 30 lane change manoeuvres in a 6 DoF moving base driving simulator. Two scenarios were used: a closing gap in the target lane and a constant gap in the target lane, with 15 repetitions per scenario. The results show high inter-driver and intra-driver variability, for both lane change duration (M=6.34 s SD-inter=0.90 s SD-intra=1.26 s) and steering behaviour (e.g. maximum steering wheel angle M=4.14 deg SD-inter=1.62 deg SD-intra=1.34 deg). The effect of the scenario was not significant for lane change duration and maximum steering wheel angles. Additionally, it was shown that lane change duration only has a medium correlation with the maximum steering wheel angle (Pearson R(585)=-.48, p\textless0.001). Furthermore, the mean and variability of the lane change duration decreased when lane changes were initiated with a shorter distance to the slow lead vehicle. Concluding, the lane change duration does not fully determine steering behaviour during a lane change, making it an unsuitable metric for determining human-like lane change trajectories. It is therefore proposed to create trajectories based on steering behaviour. It seems that drivers exhibit high variability in lane change behaviour when spatio-temporal criticality with respect to traffic is low. Higher spatio-temporal criticality limits the mean and variability of the lane change duration. Future work should determine whether this variability is the result of driver preference or indifference. Additionally, future work should implement and test human-like lane change trajectories based on steering behaviour as opposed to lane change duration.