Driving Simulation Evaluated Driver Behavior when Interacting with Automated Truck Platoons in Work Zones.
Automated truck platooning, a system that electronically "links" multiple trucks in a convoy, has been identified as an opportunity for efficiently using existing capacity and reducing fuel usage. The Iowa Department of Transportation (DOT) and Federal Highway Administration (FHWA) are exploring truck platooning technologies to better understand impacts on surrounding traffic. As a part of the FHWA Smart Work Zone Deployment Initiative, this study utilized a driving simulator and an eye tracker to examine truck platooning systems in work zones. Each simulation involved driving down a lane that is approaching a work zone, then encountering a truck platoon in the open lane adjacent to the zone. A total of 10 scenarios were conducted with each of the 32 participants. Researchers explained the meaning of “truck platoon” and the displayed signage to some participant groups (education), but did not provide any explanation to other participant groups (no education). The scenarios featured either two or four trucks per platoon, and three sign options (no sign, “Truck Platoon,” or the number of trucks). A post-simulator survey was conducted to collect demographic information and participant opinions on the effectiveness of the use of education and of the signage.
- Influence the behavior of drivers interacting with automated truck platoons and facilitate efficient throughput by teaching drivers about platoons. In all cases for the educated participants, participants followed the platoon more often that passed it. This offers evidence for the effectiveness of education in helping drivers to make a safer choice when encountering truck platoons. Results showed that education reduced the amount of distance between the vehicle and truck platoon, regardless of whether drivers stayed behind or bypassed the platoon. It also resulted in an increase in vehicle travel speed, with speeds becoming closer to the work zone speed limit (50 miles per hour), indicating increased drivers’ efficiency when passing a work zone.
- Formulate the education messages based on agency goals. Post-simulator survey results showed that drivers agreed that education is helpful in clarifying how to react to a truck platoon. If the concern is the increase in speed that could naturally occur after education, agencies should be explicit in recommending lower speeds while encountering platoons. If the goal is to promote congestion relief, agencies should educate efficient but safe behavior near work zones and decrease truck platoon sizes, as increasing the number of platooned trucks can cause drivers to speed up and bypass the platoon and decrease headway when merging into the open lane.
- Inform drivers of the number of trucks in a platoon. There was no statistically significant difference in driver behavior between signage for “Truck Platoon” versus “Number of Trucks,” but 78 percent of participants indicated they preferred signs that displayed the number of trucks. Providing platoon size can also influence driver behavior, as more than half of the participants agreed that when there were more platooned trucks, more pressure was felt.