(BBC) - Boss successfully drove around an urban environment, avoiding other cars, and covering 60 miles (85km) in less than six hours, all without any human control.
The modified Chevrolet Tahoe was one of six cars that crossed the finish line, from a pack of 11 robotic vehicles which set off at dawn. The others had to pull out after crashes or other problems.
The race was organised by the US military's Defence Advanced Research Projects Agency (Darpa) and is designed to develop unmanned vehicles that could be used in battle situations. Automotive manufacturers say the technology could eventually lead to self-driving cars.
Boss navigated around a simulated town, created on a disused US Air Force base in Victorville, in the Californian desert.
It had to deal with single and dual carriageway roads, junctions, buildings and car parks. As well as the 10 other driverless cars, Boss shared the road with more than 30 professional human drivers to simulate busy traffic.