Aiming to find the rotational inertias, the rolling resistance coefficient and the drag coefficient of an electric vehicle, a set of tests was developed based on the speed over time curves in two conditions: free acceleration on a ramp and free deceleration (coast-down) on a flat road. Since the main interest was in knowing the parameters and not only finding the resistance power for different speeds, as is usually the case for a coast-down test, an iterative analysis of both data sets was made. The methodology was validated by testing and analyzing road vehicles, because the values of the parameters were readily available, and by confronting the results of simulations for both types of tests. For the electric vehicle, redundancies and variations were used during testing for validation. The results for the road vehicles were within a margin of up to 10.4% from the reference values.