Brushfires and kangaroos were among the challenges drivers faced in the 1,864-mile-long course.
The 11th annual World Solar Challenge wrapped up on Thursday.
Competitors raced in solar-powered cars that used the equivalent amount of power used in a hair dryer.
Of the 37 teams that began the 1,864-mile-long race, 22 finished.
Teams racing sleek sun-powered vehicles across the desolate Australian Outback this week have faced brushfires, searing heat, exploding car batteries and baby kangaroos along the highway. Today the futuristic cars pushed the limits of engineering and energy efficiency as they crossed the finish line.
The 11th annual World Solar Challenge kicked off Sunday in Darwin and wrapped up today in Adelaide. Teams from universities around the world have traversed 1,864 miles of rugged terrain through the heart of Australia. Reaching top speeds of more than 70 miles per hour, each solar car is accompanied by support vehicles, all of whom must stop each afternoon at 5 p.m. and camp overnight wherever they stop.
Race director Chris Selton says the goal is to not only crown a winner, but also promote the idea of using the sun to drive cars over long distances.
"The big picture goal is to challenge people's perceptions about transport and the fuels we use," Selton said shortly after departing Alice Springs. "They are honing to perfection the most efficient electric vehicles. To see them in our cities travel at highway speeds on a couple of kilowatts is absolutely fantastic."
The race is based on the idea that a car powered by 1000 watts of solar energy car (the amount used in a hair dryer) would complete the journey in 50 hours. They are also allowed five kilowatt hours of stored energy to be used when the sun's angle is low or when clouds and rain develop. All other energy must come from the sun or be recovered from the kinetic energy of the vehicle.
The constraints of the competition have led to some unusual vehicle designs that take advantage of the latest in lightweight carbon fiber materials, photovoltaic cells and battery technology.
Of the 37 teams that began the race, 22 finished including the University of Michigan, Stanford, MIT and Principia College. UC Berkeley's team pulled out earlier this week, while Michigan held onto third place despite a damaged wheel cover.
"We took a calculated risk and increased our speed to catch up (to the Japanese team)," said Chris Hilger, the Michigan's team business manager, via satellite phone. "We went faster than what we had seen before and some crosswinds got going and damaged our wheelcover. That cost us an hour of racing time."
Along the empty roads of the Outback, Hilger and the other members of the Michigan team dodged kangaroos, emus, cows and lizards. They camped on dirt roads each night and in the morning, crews tilted the vehicle's massive solar collector to catch the first rays of sunlight to produce power.
Japan's Tokai University won the five-day race, followed by a Dutch team, and then Michigan.
The Michigan team raised more than $1 million in sponsorships to build the 16-foot long "Quantum" vehicle, which weighs 320 pounds and can reach a top speed of 105 miles an hour on a closed track.
"What we proved is that if you push yourself and push the technology, you can go a huge amount of distance and use very little energy," Hilger said.
The team may be bringing back a few lessons for the U.S. auto industry. The students built advanced electric drive trains, carbon body parts and smart systems to regulate energy use in the Quantum vehicle's electronic control system.
"There's a lot of relevance to the consumer," Hilger said. "This race goes lot to show that sustainable transportation is not too far away if the consumer is willing to make some sacrifices on comfort."