Cooperative Adaptive Cruise Control (CACC) is a driver assist technology that uses vehicle-to-vehicle wireless communication to realize faster braking and acceleration responses in following vehicles and shorter headways compared to Adaptive Cruise Control (ACC). This technology not only enhances road safety, but also offers fuel saving benefits as a result of reduced aerodynamic drag. The amount of fuel savings is dictated by the following distances and the driving speeds. So, the overarching goal of this work is to explore truck drivers’ preferences and behaviors when following in “CACC mode,” an area that remains largely unexplored. While in CACC mode, the brake and engine control actions are automated. A human factors study was conducted to investigate truck drivers’ experiences and performance using CACC at shorter-than-normal vehicle following time gaps. The “On-the-road” experiment required commercial fleets drivers to operate the second and third trucks in a three-truck string on the freeways for 160 miles in Northern California. The experiment was in mixed normal traffic without any on-site assistance of authorities, such as state police. All trucks were equipped with CACC systems and unloaded trailers. F ive different time gaps between 0.6 and 1.8 seconds were tested. Factors such as cut-ins by other vehicles, road grades, and traffic conditions influenced drivers’ experience using CACC. Other factors like time gap setting, individual differences, and route section affected drivers’ usage of CACC. These findings reveal truck drivers’ acceptance of the deployment of CACC in their truck fleets and provide useful information for decision making to promote CACC usage in the trucking industry.

Cooperative Adaptive Cruise Control (CACC) provides an intermediate step toward a longer-term vision of trucks operating in closely-coupled automated platoons on both long-haul and short-haul freight corridors. There are important distinctions between CACC and automated truck platooning. First, with CACC, only truck speed control will be automated, using V2V communication to supplement forward sensors. The drivers will still be responsible for actively steering the vehicle, lane keeping, and monitoring roadway and traffic conditions. Second, while truck platooning systems have relied on a Constant Distance Gap (CDG) control strategy, CACC has relied on a Constant-Time Gap (CTG) control strategy, where the distance between vehicles is proportional to the speed.