Audi was in position to win the 24 Hours of Le Mans for the 11th time, with its cars in the top three spots Saturday night.
Its main rival, Toyota, fell out of contention after its two cars retired.
In the 12th hour, defending champion Benoit Treluyer in the Audi No.1 led Tom Kristensen's Audi No. 2 by 1 minute, 45.111 seconds, and Marco Bonanomi's Audi No. 4 by a lap. Neel Jani's Lola No. 12 was fourth, five laps behind Treluyer.
At the end of the fifth hour, Ferrari No. 81 bumped into Toyota No. 8, which was running third and driven by Anthony Davidson. The Toyota became airborne before slamming into the tire barrier, forcing the safety car to come out.
The race was held up for 71 minutes to clean up the track and remove wrecks of both cars at the Mulsanne corner.
Davidson was carried to the circuit's medical center. The Toyota team said doctors confirmed that "the pilot is suffering from shock and back pain." He was conscious but was taken to a local hospital for precautionary checks.
"Well that was a big one! Lying in a French hospital with a broken back," Davidson tweeted. "(It) wasn't what I had in mind at this stage in the race."
Before the safety car came on, Nicolas Lapierre in his Toyota No. 7 passed Treluyer's Audi No. 1 that had been leading from the start. But Audi No. 1 took advantage of pit stops to recapture the lead while the safety car was on the track.
"We were setting a good pace and I think that leading the 24 Hours of Le Mans shows the work done by the team since the beginning of the project," Lapierre said. "We will continue to push to gain the maximum experience from this race."
Toyota had its only remaining car damaged when the race resumed. Kazuki Nakajima's Toyota No. 7 attempted a risky pass and collided with the Nissan DeltaWing in the seventh hour. Nakajima damaged the rear of his car and his crew wasted a lot of time to repair it before finally throwing in the towel in the 11th hour.
Audi also had a scare in the fifth hour when Romain Dumas' Audi No. 3 went wide at the Forza chicane and crashed into a tire barrier. However, Dumas was able to drive back to the pits for repairs.
The German manufacturer had made the best of the rolling start to take the top three spots when Allan McNish's Audi No. 2 overtook Stephane Sarrazin's Toyota No. 8 in the opening lap to take third.
But Audi No. 3, in second place, suffered a puncture and Audi No. 2 had a rear suspension problem. Both went to the pits, allowing the Toyota cars to make up ground.
Audi has won seven of the last eight races at Le Mans. Peugeot was able to disrupt the dominance of the German manufacturer in 2009.
Toyota was returning to the world's most famous endurance race, 13 years after its last participation. The Japanese manufacturer only started its testing program in January but made quick progress to become Audi's main challenger at Le Mans.
"Motorsport can be a rollercoaster of emotions and we experienced great joy to see Nicolas taking the lead of Le Mans, only for the shock of Anthony's accident," Toyota team president Yoshiaki Kinoshita said. "It was a huge relief to hear he is okay."
A total of 56 cars started the 80th edition of the French endurance race, which will end Sunday afternoon.