California Partners for Advanced Transportation Technology

This report shows a successful application of 5.9 GHz DSRC with 100 ms update intervals to coordinate the automatic longitudinal control of a platoon of three Class 8 tractor-trailer trucks. The trucks were tested not only in constant-speed cruising conditions, but also through acceleration and deceleration profiles, up and down grades, and in platoon join and split maneuvers using the DSRC coordination. These tests showed acceptable vehicle following accuracy, ride quality and platoon stability. The gaps between the trucks were varied between 10 m and 4 m to evaluate the effects of aerodynamic drag reductions on fuel savings. The most complete set of drag data, at the 6 m gap, showed fuel savings of about 4-5% for the lead truck and in the range of 10% to 14% for the following trucks. The effects of platoon gap variations between 10 m and 4 m were more difficult to determine with certainty because strong ambient winds during those tests led to large differences in the results depending on the truck direction of travel, but the results imply a significant potential for larger savings at the shorter gaps.