5.4 Articulated Trucks
Trucks vary from light-duty to heavy-duty and articulated trucks. Trucks may also be used in different ways from urban delivery use to international long distance transport. An articulated commercial truck with an average load and maximum total weight of 40 t will be considered here. An articulated truck is composed of a tractor and a trailer. Large trucks are the dominant modes of road transport in Europe as well as the U.S. and account for a significant portion of the transportation sector’s fuel usage. It is assumed that these trucks mainly drive on highways.
5.4.1 Specific energy savings
Either direct or indirect energy savings can be achieved by weight reduction. If “… the vehicle is lighter, energy use for hauling is reduced (if the cargo is volume-limited), or additional cargo can be carried (if weight-limited). In either case, the energy use per ton- mile carried is reduced” [STODOLSKY et al.1998]. We will deal with the two options for energy savings separately. First we will discuss the direct fuel savings by weight reduc- tion (for volume-limited cargo) and afterwards indirect fuel savings by additional cargo (for weight limited cargo).
Fuel savings by weight reduction are estimated by extrapolation of the energy con- sumption of trucks with different loads and by considering the share of aerodynamic re- sistance and other resistance factors on the fuel consumption. A comparison with long distance buses is also undertaken.
Load of Truck
Rural main roads
0.086 IFEU 2003
The fuel consumption of trucks is highly dependent on the load. The values in Tab. 11 are based on tests of today’s articulated trucks and show that the fuel consumption of a fully loaded truck (40 t) is more than 30 % higher for highways and even 60 % higher for urban roads compared to the empty truck. On the basis of [IFEU & SGKV 2002], the specific fuel savings on a highway by a weight reduction of 100 kg are estimated to be around 0.038 l/ 100 km. This extrapolation may be critical due to the different driving be- haviour depending on the load, but has also been suggested by experts ([EBERLE
Tab. 11: Fuel consumption of articu
Extrapolation [l/(100km*100kg)] Source: [IFEU & SGKV 2002]
Empty (0 % load)
Average (47 % load)
Full (100 % load)
Approximations may also be made from the share of the weight independent aerody- namic esistance of the total resistance. The average share of aerodynamic resis- tance for articulated heavy trucks at highway speeds is estimated in the range of 60%