NASCAR links belt, physics in report

ATLANTA — A broken seat belt, complex laws of physics and simple bad luck came together in a fraction of a second as Dale Earnhardt's car hurtled toward the concrete wall at Daytona International Speedway, a long-awaited NASCAR investigation into his death concluded yesterday.

In the most detailed examination yet of the Daytona 500 crash that killed the racing legend Feb. 18, experts hired by NASCAR demonstrated how they believe Earnhardt was doomed by a complex chain of events, including a collision with fellow driver Ken Schrader and the unprecedented failure of his left lap belt.

The result: The back of Earnhardt's head, unprotected when his helmet momentarily slipped out of place, struck either his steering wheel or the left side of the car, the experts concluded.

The six-month investigation, which cost more than $1 million, featured crash simulations and computer-enhanced video to explain the accident, and DNA tests to prove that a broken seat belt shown in photos was in fact the belt from Earnhardt's car.

But the investigation left unanswered many questions about the circumstances surrounding the death of the seven-time NASCAR champion — particularly the role of the broken seat belt. NASCAR's experts repeatedly declined to blame the belt failure for Earnhardt's death — but made repeated references suggesting that it was a major contributing factor.

And the findings directly contradicted those of an independent court-appointed expert who concluded in April that Earnhardt died of a violent head whip that fractured the base of his skull. That type of injury, which killed two NASCAR drivers in the year before Earnhardt, can be prevented by use of a head-and-neck-restraint system that NASCAR now recommends, but has not made mandatory.

That expert, Dr. Barry Myers, also concluded that Earnhardt would have died regardless of what happened to his seat belt.

One of NASCAR's principal researchers, accident-analysis expert Dr. James Raddin, conceded that the complicated findings announced might leave some unsatisfied.

"There is a tendency to want to have a single finding," said Raddin, of Biodynamic Research Corp. in San Antonio.

"Typically, when something that normally works pretty well, if just one thing goes wrong, it tends to still work pretty well," Raddin said. "When multiple things come together and go wrong together, that's when you have problems. And that's what happened here."

The explanations laid out by Raddin and fellow researcher Dr. Dean Sicking, an accident-reconstruction specialist at the University of Nebraska, were anything but simple. But they offered the first detailed and scientific analysis of the crash that took Earnhardt's life.

The researchers — using the same experts who restored and enhanced the Zapruder film of John F. Kennedy's assassination — examined the videos shot by seven different track cameras of the Earnhardt crash, Sicking said.

Sicking showed how the crash unfolded on the last lap of the Daytona 500 as Earnhardt, running in third place, made contact with the No. 40 car of Sterling Marlin. Earnhardt's No. 3 car veered left toward the infield and then back to the right into traffic, where he was struck by the No. 36 car of Schrader.

Both Earnhardt and Schrader were moving at speeds ranging from 156 mph to 161 mph when they collided, but Schrader suffered only minor injuries. That was no fluke, Sicking said.

That's because, when Schrader and Earnhardt collided, the impact spun Earnhardt's car slightly, and so it hit the wall at an angle about 2 to 3 degrees steeper than Schrader's, Sicking said. It translates into a 25 percent increase in the energy of the crash, Sicking said, "meaning a significantly more severe hit for the No. 3 car."

The force of the crash was worsened because Earnhardt's car did not rotate as it hit the wall, as cars normally do, which helps absorb the energy of a crash, Sicking said. The right front of Earnhardt's car slammed into the wall with an impact similar to a parked car being hit by a car traveling at 75 to 80 mph.

Raddin said the lap-belt attachment points were on the floor well behind the seat, rather than further forward as the manufacturer — Simpson Performance Products — recommends.

Raddin did not criticize the belt installations, and he emphasized that the belts were not improperly adjusted. Both of those statements would be vigorously disputed by the belt's manufacturer in a news conference soon after NASCAR released its findings.

The left seat belt broke under the strain in a phenomenon known as "dumping," Raddin said. Simply put, the belt bunched up along one end of the metal adjuster, and the loading of the crash caused it to rip from one side to another, Raddin said.

That left Earnhardt's left side — and the unprotected back of his head — moving forward in a fatal arc, Raddin said.

NASCAR said that beginning next season it will install "black boxes" in cars, similar to flight-data recorders on airplanes, to help understand the forces during crashes and improve safety.