”Ummmm, who’s got that restart key?”

The speaker is a slightly worried Mike Wahlstrom, co–team leader for the University of Waterloo’s Challenge X team. The impetus for his question is your intrepid reporter, who has managed to stall the Canadian team’s unique, fuel-cell-powered Chevy Equinox. It won’t restart, and we’re blocking a traffic lane at midday in downtown Detroit.

The cause of the problem? My aggressive driving: mimicking any suburban commuter, I floored the accelerator as I pulled into oncoming traffic. Because one of the two electric motors was disabled, as Wahlstrom explained after we got the car restarted, the vehicle controller fed too much voltage into the remaining motor, whose control software triggered a shutdown to protect it from burning out.

Flooring a car isn’t unusual, though; drivers do it every day. And that challenge—making a highly modified SUV usable by everyday consumers—lay at the heart of the third year of Challenge X. It’s a competition funded by the U.S. Department of Energy and dozens of other sponsors, including General Motors Corp. GM donated brand-new 2005 Chevrolet Equinoxes to the 17 college teams, which each must attempt to build a sport-utility that uses less petroleum and emits fewer pollutants and greenhouse gases.

Following a full year of computer modeling, simulation, and design testing, the teams set to work with cutting torches in 2005. In last summer's event to end Year Two, their modified engineering prototypes—known by the industry as ”mules” for their often-balky behavior—were put to the test at GM’s Desert Proving Grounds in Mesa, Arizona.

The challenge for Year Three was to improve those mules to a ”99 percent acceptability level.” In English, that means making them something a soccer mom could drive—ideally without ever noticing the technology changes, except perhaps at the gas pump.