Vehicle Platooning project in Europe
Europe
Safe Road Trains for the Environment
Summary Information
The overall concept of Safe Road Trains for the Environment (SARTRE) is to have a group of vehicles driving together with a lead vehicle, driven normally by a trained professional driver, and several following vehicles driven fully automatically by the system with small longitudinal gaps between them. Driving in this way in a platoon brings benefits in fuel consumption, safety and driver convenience. In addition to investigating the concept, a demonstrator system has been developed consisting of 5 vehicles: a lead truck, a following truck, and 3 following cars. An offboard system has also been developed to allow a potential SARTRE driver to find, and navigate to, a suitable platoon, although this has not been fully integrated into the vehicle system.
The project investigated the human factors aspects of platooning from the point of view of the lead driver, the following drivers, and the other road users. The demonstration system has been successfully tested on test tracks and public motorways, and demonstrated to industry stakeholders as well as members of the press. Using these vehicles, the fuel consumption benefits of platooning have been measured. The SARTRE project measured the fuel consumption individually for each vehicle in order to compare it with the fuel consumption while platooning. The distances tested for the full platoon system were 5, 6, 7, 8, 9, 10, 12, and 15 meters. A 2 truck platoon was also tested at 20 and 25 meter gaps. Measurements of the fuel consumption are not available for cars in the full platoon system at gap sizes of 7 meters and below. The reason for this is that an analysis of the results showed that an internal safety function in the cars triggered a pre-charging of the brakes while driving at such close distances. This pre-charging affected the fuel consumption and hence the measurements are excluded from the graphs.
FINDINGS
The results show that there is an important decrease in fuel consumption when platooning at shorter distances. For example the following truck saw the highest fuel savings of 16 percent at a gap of 5 meters. When the gap was increased to 15 meters the following truck still showed fuel savings of just over 8 percent. The following vehicles fuel savings ranged from 15 percent at a 7 meter gap to just over 4 percent at a 15 meter gap. This behavior follows a similar trend to what has been previously researched and also similar to that of the simulation results. The below graph show all of the results by gap distance and vehicle location:
Percentage of fuel savings of each vehicle in the platoon at varying gaps (SARTRE Final Report, page 35).
