Experimental Investigation of the Aerodynamic Benefits of Truck Platooning: Two- and Four-Vehicle Platoons

A series of scaled wind tunnel tests are conducted to investigate the aerodynamic benefits of heavy vehicle platooning and the availability of cooling air for trailing vehicles on two- and four-vehicle platoons. To measure the aerodynamic drag, scale models are mounted onto a splitter plate by means of a low-friction linear bearing and a load cell located within each model trailer. In addition to drag, pressure measurements are made with a pitot probe positioned at the center of each model radiator grill. Four homogeneous, two-vehicle platoons are tested for spacings up to 300′ and six heterogeneous, four-vehicle platoons are tested with spacings ranging from 30′ to 50′. For the heterogeneous platoons, configurations are tested with one distinct heavy vehicle or medium duty vehicle, as well as with four distinct heavy vehicles. Over spacings of 15′ to 80′, the best performing homogeneous, two-vehicle platoons are comprised of a Supertruck tractor and straight frame trailer. Likewise, for the four-vehicle, heterogeneous platoon with one distinct vehicle, the greatest performing platoon for all vehicle spacings is the one in which the Supertruck vehicle is in the lead position with three following long-sleeper tractors with straight frame trailers. On the other hand, for the heterogenous, four-vehicle platoon with a medium duty van, the best platoon performance is when the van is in the last platoon position, which has the benefit of making it easier for the van to join an existing, long-haul heavy vehicle platoon. When all four heavy vehicles are different, the overall platoon performance is relatively insensitive to vehicle repositioning within the platoon, which provides the benefit of robustness to changes in platoon structure that may arise in real-world operations.