Overtaking automated truck platoons: Effects of platoon organisations and traffic situation on driving behaviours of nearby manual vehicle drivers

Abstract

Automated truck platooning is a promising technology that is expected to be mainstream within the next decade. For the foreseeable future, automated truck platoons will coexist and interact with human drivers. Resembling a train-like formation, automated truck platoons may present challenges for drivers wishing to overtake them, and it is not currently clear how these new formations affect driver behaviour. Therefore, this paper aims to examine driver behaviours in the overtaking process under various platoon organisations. A high-fidelity driving simulation experiment was conducted to investigate the influence of platoon speed (80 km/h and 100 km/h), size (three trucks and five trucks), inner gap (5 m and 25 m) and the surrounding traffic situation, e.g., the presence of a lead vehicle, on drivers’ overtaking behaviour. Thirty-eight participants were recruited in the experiment. Results revealed that compared to 80 km/h conditions, the 100 km/h conditions prompted more drivers to exhibit extreme behaviours—either failing to overtake or performing a risky overtaking. Regarding platoon size, drivers tended to deviate farther from the lane center to maintain a larger lateral distance from the platoon under five-truck conditions. With respect to the inner gap, a 25 m inner gap significantly reduced the proportion of successful overtaking maneuvers. Moreover, in critical conditions, a 5 m inner gap extended drivers’ response time but did not significantly impact collision probability. The presence of the lead vehicle increased drivers’ mental workload and impaired longitudinal stability. These findings may offer insights for managing automated truck platoons. For instance, the platoon speed and inner gap can be regulated in different traffic conditions, to optimize efficiency, while ensuring safety for all road users.