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 race 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 auto racing's biggest star in February, specialists hired by NASCAR demonstrated how they believe Earnhardt was doomed by a complex chain of events, including a collision with fellow driver Ken Schrader's car 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 specialists 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 belt. NASCAR's specialists 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 refused to make mandatory.
That specialist, Dr. Barry Myers, also concluded that Earnhardt would have died regardless of what happened to his seat belt.
Ten days ago, The Orlando Sentinel reported that NASCAR's investigation would not blame Earnhart's fatal injury on a broken seat belt. The story was based on interviews with sources close to the investigation, who also cautioned that NASCAR might not release all the information accumulated by the investigators.
The sources said last night that the investigation's findings did not contradict their predictions in the Sentinel's previous reporting: "It is NASCAR's position that the broken seat belt did not cause Dale Earnhart's death. Absolutely."
One of NASCAR's principal researchers, accident analysis expert Dr. James Raddin, conceded that the complicated findings announced yesterday might leave some unsatisfied.
"There is a tendency to want to have a single finding," said Raddin, of Biodynamic Research Corp. in San Antonio, Texas.
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 home movie of John F. Kennedy's assassination--examined the videos shot by seven different track cameras of the Earnhardt crash, Sicking said. They used the Global Positioning System transmitters installed by broadcasters in the NASCAR race cars, which update the car's positions five times a second, to help determine their speed and direction.
Using that data, along with analysis of skid marks, 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.
In its two-volume report, 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, the Associated Press reported.
Both Earnhardt and Schrader were moving at speeds ranging from 156 and 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.
Earnhardt would have sustained an impact of 45 to 68 g-forces, well within the range of a fatal crash, the NASCAR report said.
It was "a worst-case scenario from an occupant risk standpoint."
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 75 to 80 mph.
To survive such a crash, Raddin said, "Things have to work right."