Abstract: A propulsion system for traction vehicles utilizing separately excited electric traction motors in which a level of reverse motor torque is produced when speed control is released to effect a dynamic drag on the vehicle. The system simulates in an electric vehicle the dynamic drag effect characteristic of an internal combustion engine driven vehicle when the accelerator is released. The effect is attained by providing a motor armature regenerative current path through a load resistor and by maintaining motor field current at a selected minimum level when the speed control is released. A function generator adapted to regulate motor field current as a function of motor armature current provides a minimum field current signal when armature current is less than a selected value to thereby maintain field current and motor torque when the speed control is released.