some people watch for the wrecks. you got people there to watch rock crawling. you got people who can't wait to see what happens if one's going to fall off rock, and they do. >> the competition is fierce. the custom built rock crawlers can be dangerous. >> in essence you're trying to defy gravity to some extent. sometimes you don't win. gravity does. you are in a confined area. you have gasoline and any time you have fuel in a vehicle, possibility of a fire. >> this competition is a timed course, where drivers receive penalties for errors like hitting cones or going out of bounds. >> if you accomplish that course in enough time, then you had time to go try the bonus line. >> bob runs through the course without a hitch, and approaches a 20-point bonus obstacle aptly named the wall. >> crawler went up a little ways, slid down, so we backed up.