The HMD is the work of Britain's Defence Evaluation and Research Agency (DERA) and only one has been built. Its raison d'etre centers on a British Army need highlighted during the Gulf War. The new type of truck is capable of keeping pace with fast-moving tanks across difficult terrain, but with a high-performance capability on "metalled" roads. The result is the HMD, which DERA underlines is a technology demonstrator; it uses mainly off-the-shelf components and was built by Ricardo Special Vehicles. It has a Cummins six-cylinder, 10-L, turbocharged and intercooled engine providing 261 kW (350 hp) at 1900 rpm and 1695 N—m (1250 lb—ft) of torque at 1200 rpm. Drive is through a logic-based Eaton CEEMAT (Converter Enhanced Electronically Managed Automatic Transmission) gearbox with nine forward and two reverse gears. All six wheels of the HMD can be steered, although the rearmost only at low speed and in the opposite direction to the front two axles. A ZF steering system is used. Tires are Michelin 475/80R20 XML with Vorwerk beadlocks for low pressure running. There is a CM Automotive Explorer central tire-inflation system for adjusting pressures. It is two-channel unit, with one operating on front-axle tire pressures, the second on the remaining two axles' pressures. Brakes are Rockwell Dura-Master inboard discs, and there is a Wabco six-channel anti-lock system. Suspension comprises a Rockwell/Timoney 5000 off-highway series independent system to all three axles. Its optional, adjustable system, uses Airlog control software and adjustable Hydrostruts instead of the spring damper system, facilitating adjustable ride control. Howden Aircontrol provides the air conditioning and nuclear, biological, and chemical protection for the cab environment.