In auto racing, the most spectacular crashes usually happen during weekend contests at tracks surrounded by fans. But since last spring, some of NASCAR's most important collisions have taken place at low speeds behind a suburban office building near Charlotte, N.C. There, at NASCAR's year-old R&D Center, engineers are conducting tests to try to assure that fewer of those weekend smashups end in tragedy. "We take good stuff and turn it into junk," says R&D chief Gary Nelson, picking at a pile of twisted scraps his team tested recently. Walking inside the garage, Nelson points to a car featuring a thin aluminum driver's seat with no shoulder support. "Can you imagine racing in that today?" he asks, as if looking at an antique. But the seat in question was state-of-the-art in 2001.

That year marked a dark turning point in NASCAR history--one that will be commemorated this weekend at the season-opening Daytona 500, where Dale Earnhardt died on the final turn three years ago. Earnhardt was the fourth driver fatality in just nine months, leading NASCAR to bring in a team of outside experts to investigate. The experts helped racing officials understand why some of their basic approaches to safety were simply wrong. By 2002 NASCAR had hired an R&D staff to devote its full attention to computer models and safety brainstorming. The team began by adding black boxes to every car to collect crash data. By last season, housed in its new facility, NASCAR's safety team was rapidly rolling out innovations: new fire extinguishers, cockpit carbon-monoxide filters, new tethers to prevent wheels from flying off in wrecks and rooftop escape hatches. Outside the cars, five tracks have new walls installed that are designed to absorb crash energy. "For 50 years, most of the money and technology were thrown at making the cars go faster," says Joe Menzer, author of "The Wildest Ride: A History of NASCAR." "Now they're throwing more money and brainpower at making racing safer."

NASCAR never ignored safety concerns, but for years its efforts were ad hoc, sporadic and driven by crises. After a rash of fatal, fiery crashes in the 1960s, for instance, the sport mandated fireproof suits and extinguishers. Then came more solid cockpits, to prevent "intrusions" when cars collide or roll over. But even before the 2000-2001 deaths, some race teams thought the cars had become too rigid, causing drivers' bodies to bear the brunt of the forces generated in a wreck. In response, NASCAR began working to create more crushable, energy-absorbing bumpers. But when outside consultants arrived on the scene after Earnhardt's death, the experts suggested NASCAR would see the biggest safety returns by devoting most of its effort to finding new ways to strap drivers more securely into a form-fitting cockpit and padding racetrack walls. "Our priority list has changed dramatically," says Nelson, 50, who directed NASCAR's Winston Cup circuit before taking the R&D job.

Today every driver wears a mandatory head-and-neck restraint and more secure seat belts. Some drivers now use wraparound carbon-fiber seats that look like something you'd find on a space shuttle. By the end of this year, most tracks should have the new steel-and-foam walls. Only now is NASCAR turning its attention back to making cars better able to dissipate the energy of a crash. "Once you fix your biggest problem, your biggest problem is something else," says Dean Sicking, a University of Nebraska safety expert. The next big problems may be solved by the evolving "Car of the Future" prototype, featuring new reinforcement bars, more crush zones and a better-protected cockpit that's moved a few inches toward the center of the vehicle to protect drivers in broadside "T-bone" crashes. They should hit racetracks by 2007.

Seventy miles north of NASCAR's R&D Center at the garage run by Petty Enterprises, those safety innovations are particularly meaningful. In 2000, Adam Petty, a 19-year-old up-and-coming driver (and the son of current driver Kyle Petty), died in a wreck on a New Hampshire track. Standing amid half-built cars inside the garage last week, family patriarch Richard Petty, who retired as NASCAR's top record-holder in 1992, says he doesn't waste time wondering whether the new safety devices might have spared his grandson: "At the time it happened, [Adam's car] was as safe as we knew how to make it." Race cars will never be 100 percent safe, he says, spitting tobacco juice into a garbage can, but "if you keep making them 5 percent safer, that's a big jump." Asked for his ideas on how to make racing less dangerous, Petty, 66, envisions a day when injured drivers can be removed from cars still enclosed in their wraparound seats, to limit movement that can exacerbate injuries. "If you've got him in a capsule, let's fix it so you can take the whole thing to the hospital before they even bring him out," Petty says. Back at the NASCAR R&D center, they say it's an idea that's already on their drawing board.