External communication displays for connected truck platoons in mixed traffic : a federated simulator study

Abstract

Truck platooning is anticipated to be the first widespread deployment of connected or automated vehicles (CAV). In addition to familiarizing the public with the function of CAV, a truck platoon has proven benefits to fuel consumption by minimizing drag. These are the primary motivations that have caused companies to develop and deploy these systems, but there are still obstacles opposing their implementation. One obstacle is the issue of communication between CAVs and the surrounding traffic. For example, research has shown that communication between CAV and pedestrians and cyclists is facilitated by using external status displays on the CAVs. In order to investigate the communication between truck platoons and surrounding traffic, a similar model is proposed in this study. The scenario examined in this study involves trucks forming a truck platoon. Two different external displays in addition to a control display were evaluated for how surrounding traffic behaves while the trucks form their platoon. The three displays are the control (no signal), the word "PLATOON," and a graphic of two trucks with a link. Each of the displays were tested using a federated truck simulator and passenger vehicle simulator. The approaching truck was driven by the same human driver up until the completion of platooning while the passenger vehicle was driven by the research participants. The simulation scenario involved a passenger vehicle following a semi-truck while an approaching truck comes up from behind the passenger vehicle to form the platoon. The actions taken by the passenger vehicle to clear the way for the approaching truck were observed and recorded. After the participants were exposed to the signs once, they were provided with an explanation of truck platoons and were able to ask questions before experiencing three displays scenarios again. Overall, the primary performance result was that the text display after being provided with information on truck platoons significantly changed the behavior of the passenger vehicle. Furthermore, as in the AV-Pedestrian studies, participants indicated that the external displays were useful. In conclusion, though the behavior was not drastically affected, the results indicate that the displays provide the passenger vehicle drivers with important information that they want to have and that drivers tend to move out of the way when they learn that a truck platoon is forming around them.