The power and energy demand necessary in order to set a motor vehicle in motion is determined by the forces of resistance on the road that have to be overcome. These resistive forces are classified into road resistances limited to a steady-state driving condition, meaning at a constant speed, and road resistances that are generated by vehicle acceleration.
The resistance forces that act on a vehicle moving at a constant speed, can be classified into three groups:
- Wheel resistance,
- Aerodynamic drag,
- Climbing resistance.
In a transient driving condition, the additional component of driving resistance includes:
- Acceleration resistance.