General Motors delivers the HUMMER H3 to the law enforcement market. Powered by the Vortec 3500 engine with dual overhead cams and variable valve timing, the H3 features a combination of power and greatly improved fuel economy, with fuel economy ratings of up to 20 miles per gallon. The heart of the truck's off-road capability is its electronically controlled full-time four-wheel-drive system. The H3 can ford 16 inches of water at 20 mph or 24-inch streams at a 5-mph pace, climb 16-inch vertical steps and rocks, make its way through deep sand and race over sandy surfaces. It also features a fully locking rear differential, traction control, underbody shielding and GM's StabiliTrak vehicle stability enhancement system.