A series of prototypes has culminated in an advanced hybrid electric vehicle (HEV) that can be driven and evaluated like any other test car. An Escort station wagon is the basis for the vehicle which is equipped with a 5O kW (68 hp) three-cylinder engine and a 30 kW electric drive coupled to an automatic transmission and to a 7 kWh nickel-cadmium battery. The engine and electric drive are fully integrated and are automatically blended to meet the driver's demands. In general the vehicle runs on the electric drive in slow city traffic, on the engine when cruising at highway speeds, and on both when hard acceleration is required. The electric drive captures regenerative energy to improve the vehicle's overall efficiency. The design of this vehicle and the trade-off issues are discussed