>> risks are very high. fred's had our worst injury. he was doing about 64, touched wheels with another car, slid off the road, hit a tree, and set down. all that happened in about 1.2 seconds. >> what broke? >> shattered the tibia, fibula. i have ten pins and two plates. >> fred's knee exhibit "a." fred's cautionary tale is more sufficient to make me think twice about strapping myself into a gravity car but fran's enthusiasm is impossible to overcome, plus it looks like fun. >> i'm assuming this is only sensible way. >> if there was any sense involved in this, you wouldn't be here. >> yeah, the word "sensible," really i didn't notice it on your facebook page. >> you never, ever want to touch the brakes. >> okay. >> this whole thing is about momentum and maintaining that momentum. all these other guys that are going to be around you, they'll