driving a gravity car requires a delicate balance between competitiveness and self-preservation. i'm going over 50 miles an hour right now in a glorified tin can. trying to make my way through a field of fellow nut jobs with two very different voices in my head. >> we never, ever want to touch the brakes. all these other guys that are going to be around you, they'll eat you alive. >> you're going to get a lot of confidence. just take it easy. >> right now, the fran side is winning. i'm downright allergic to that brake. but then -- >> he's going to lose it. >> -- there's trouble in front of me. damn it. >> i need to make a decision. >> stay clear of it. >> turns out my own level of homeostatic risk is most comfortable outside the wreckage of a major collision so i hit the brakes, but that's all it takes to put me at the end of