Lingenfelter was racing R.J. Simrock in the semifinals of the Mazda NHRA Sport Compact World Finals at Pomona Raceway when he lost control of his Summit Racing Equipment Chevy Cavalier, crossed the centerline, and hit the guardwall in the opposite lane. According to witnesses, it appeared that Lingenfelter may have been knocked unconscious upon impact, as his car proceeded off the end of the track under power before coming to rest against a safety barrier at track’s end.