NASCAR may be dominated by gas-guzzling racers, but its pace car this weekend is decidedly kinder to the environment. The motorsport league's Sprint Cup race in Richmond on the 26th (delayed from the 25th due to rain) has Toyota's hydrogen-powered Mirai as its pace car -- the first time a fuel cell car has had that distinction at a NASCAR event. This is largely a publicity stunt to build up hype for the Mirai's Californian launch later this year, but it shows that hydrogen cars have the performance needed to keep up with stock cars during yellow flags. The real challenge will be getting the actual competitors to go green. While there have been hydrogen-fueled race cars before, the odds are that NASCAR and its fans aren't eager to abandon roaring V8s any time soon.