The US 4×4 ULTRA AP (Armoured Patrol) was developed by the Georgia Tech Research Institute, the applied research arm of the Georgia Institute of Technology, for the U.S. military and the Department of Defense project to replacing the HMMWV. The ULTRA AP vehicle was unveiled in September 2005 under contract from the Office of Naval Research. This was followed in 2009 with the ULTRA II, which was more focused on further developing the crew compartment.
The vehicle was built on the skeleton of a Ford F-350 truck, combining the safety features and manoeuvrability of a commercially available truck with advancements in blast-deflection technology and materials. This vehicle was built for the U.S. Military to showcase possible technology and safety improvements to the Humvee (HMMWV).
The Georgia Tech Research Institute continued work on the project, eventually releasing the ULTRA II concept, also designed and tested for the Office of Naval Research. The new crew-protection concept builds on the earlier GTRI research on concepts for light armoured vehicles. A blast test conducted with the Ultra II at the Aberdeen Test Center showed that the vehicle could protect its occupants from improvised explosive devices.
The crew compartment was designed to fit six people: a driver and commander, facing forward, and two pairs behind them facing opposite sides of the vehicle. This design focuses on moving the crew away from external walls to reduce injury from side blasts, allows the blast-resistant seats to be frame-mounted, and reduces the time it takes to exit the vehicle.
The crew compartment uses a “space frame” constructed from tubular steel, similar to the construction of off-road vehicles, especially those involved in off-road racing, and an armoured steel skin provides structure and blast protection. Additional armour can be modularly bolted to the vehicle and easily reconfigured.