Assessment of the Effect of Training on Automated Truck Platooning and Signage on Driver Behavior When Approaching Work Zones.
Missouri, United States
Investigation of Autonomous/Connected Vehicles in Work Zones
Summary Information
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.
METHODOLOGY
For the driver simulator tests, participants were asked to start in the right lane while approaching a work zone involving a right lane closure. As the subject-driven vehicle approaches, a truck platoon appears on the left lane with the leading truck driven by a research assistant. The human subject would then decide when to merge to the open lane and whether or not to overtake the truck platoon before merging.
Seven measures of effectiveness (MOEs) and eye movement were collected during the driving simulation:
- driver behavior (follow platoon, bypass platoon, squeeze into platoon*)
- distance between the work zone and vehicle at the merge time;
- vehicle travel speed
- if the driver chose to stay behind the platoon, the headway after the vehicle merges into the open lane
- if the driver chose to bypass the platoon, the distance between the vehicle and front of the leading truck
- braking data; and
- blinker usage. Driver behaviors were classified into three categories: the driver slows down and stays behind the truck platoon, speeds up to bypass the platoon, or goes between platooned trucks.
FINDINGS
- In general, education led to an increase in speed regardless of the number of trucks in a platoon. When drivers chose to follow the two-truck platoon education, resulted in a 12.9 percent increase in vehicle travel speed and a 30.1 percent decrease in headway distance.
- For no-education followers, “Truck Platoon” and “Number of Trucks” signage alone resulted in an 8.66 percent and 6.74 percent increase in speed, and a 12.88 percent and 13.13 percent decrease in headway distance, respectively.
- Education paired with “Truck Platoon” signage resulted in a 7.57 percent increase in speed and a 16.47 percent decrease in headway distance. Education paired with “Number of Trucks” signage resulted in a 6.22 percent increase in speed and a 21.20 decrease in headway distance.
- The use of truck signage led to a 6.4 to 17.8 increase in the number of drivers who chose to bypass the platoon.
*None of the drivers attempted to squeeze into the platoon
