Abstract
Investigations have shown that the air drag coefficient of some currently produced vehicles can be reduced to 30%. Wind-tunnel tests were carried out on a 38-ton long haul vehicle using a variety of fairings, air deflectors, air dams, advanced mudguard contours, side shields and trailer front cladding. Tests were carried out on two identical vehicles one in standard form and the other fitted with various aerodynamic devices. Fuel consumption tests were carried out on a route of approximately 20000 km on the Munich-Stuttgart motorway at an average speed of 70-80 km/h. Fuel consumption vas related to metered driving at a wind speed of less than 3m/sec and results correlate well with those of the wind tunnel tests.