What caused the bumps is anyone's guess. One theory is that because NHIS requires heavy braking around the turns, the constant friction of those lead-footed stops gradually and slightly wore some of the track away. There was a bump in the entry to . . . I think what it amounted to, since this track is such braking, thousands of laps with heavy cars kind of rippled it up. It's not correct to say that the bumps caused either of the fatal accidents.
Mechanical problems have to be considered as well.
The cause of both crashes was determined to be a stuck throttle, and Leighton said that's the verdict he believes. Every racetrack holds its own challenges, and NHIS is no exception. While those characteristics might be considered unsafe, every track has something to make driving difficult. It's a flat-track thing. You don't have any bank to slow the car down.