Theoretically a number of indices can be used. In particular, the description of the engine elasticity is interesting. For passenger cars this means that a high traction force can already be transferred at low speeds. This reduces the need for frequent gear changes and hence increases driveability. The speed elasticity represents a measure of elasticity.
In trucks, however, at decreasing speeds or driving velocity, an increasing traction force is required, e.g. when driving on gradients. The torque elasticity serves as a measure here.
The figure shows the indices of different vehicle engines. As it can be proved here, that the total elasticity E=em. en does not make sense.