Sunrayce 99 was an intercollegiate solar car race sponsored by General Motors, EDS, and the US Department of Energy. The race began on June 20, 1999 in Washington, D.C. and finished on June 29, 1999 at Epcot Center in Orlando, Florida. The event was won by the University of Missouri at Rolla (now Missouri S&T). Sunrayce 99 was the fifth and final race in the Sunrayce series and was followed by the first American Solar Challenge in 2001. The overall success of the event was limited by difficult weather conditions. Teams battled clouds and rain throughout the race, and no team avoided having to trailer their car for at least part of the race route.
Teams were allowed deviate from the traditional lead–acid battery technology for the first time in Sunrayce 99 when nickel–metal hydride batteries were approved for use. The new battery technology offered equivalent capacity to lead acid batteries but weighed several hundred pounds less. Nickel–metal hydride batteries were very expensive at the time, so only the most well funded teams could afford them. Unfortunately the rainy weather and slow speeds neutralized the advantage of the new battery technology.