The Humvee HMMWV is a military 4WD motor vehicle by AM General and is the replacement vehicle for the M151 series jeeps. Its mission was to provide a light tactical vehicle for command and contol, special purpose shelter carriers and special purpose weapons platforms throughout all areas of the modern battlefield. In February 1981, the U.S Government invited proposals for a new High Mobility Multipurpose Wheeled Vehicle. AM General was one of the companies that submitted proposals. During the government's testing of the Humvee prototypes, AM General engineers made various design modifications based on performance issues raised by the government. Since its inception, the HMMWV underwent numerous design and configuration updates and changes including technological, environmental, operational and safety improvements, such as higher payload capability, radial tires, 1994 Environmental Protection, Agency emissions update, commercial buket seats, three-point seat belts, four speed transmissions and more.