 Nearly four hours into the race Scotsman Peter Dumbreck was battling amongst the race leaders when his CLR suffered the same instability and became airborne , this time vaulting the circuit 's safety barriers and crashing in an open field after several somersaults . This and earlier incidents led Mercedes not only to withdraw its remaining car from the event immediately , but also to cancel the entire CLR programme and move the company out of sports car racing . The accidents led to changes in the regulations dictating the design of Le Mans racing cars as well as alterations to the circuit itself to increase safety . 
