A method for determination of a first parameter RF which represents a motive force capacity of a motor vehicle (1) provided with a power train which may assume various transmission ratios for propulsion of the vehicle (1). The vehicle includes an engine (10) and a gearbox (20). The first parameter RF is determined on the basis of a difference between a first motive force FMax and a second motive force FDr. The first motive force FMax is a maximum motive force available for the vehicle (1) at a current transmission ratio. The second motive force FDr is a current running resistance for the vehicle (1). There is a use of such a parameter. A computer program, a computer program product, a system and a motor vehicle related to such a parameter are disclosed.