On the final turn of the final lap of NASCAR's premiere event, Dale Earnhardt slammed his famed black No. 3 Chevy into the wall at the Daytona 500.

 The seven-time Winston Cup champion, the sport's biggest star, was killed instantly.

 "Dale Earnhardt is to Winston Cup what Elvis Presley was to rock 'n' roll," said Larry McReynolds, Earnhardt's former crew chief. "When Elvis died, the music didn't stop but it definitely changed."

 The fallout led to a turbulent season, marked by a $1 million investigation into Earnhardt's death and a focus on safety. NASCAR president Mike Helton called it a "let's-see-what-you're-made-of type of year for the sport."

 It overshadowed everything else in auto racing's other circuits, which had their own tragedy and triumphs.

 From the crash that cost CART star Alex Zanardi his legs, to Michael Schumacher's dominating season in Formula One and the Indy Racing League's crowning of 22-year-old Sam Hornish Jr. as its new champion, none of it dimmed the spotlight and scrutiny NASCAR found itself under.

 Not even the success stories in NASCAR -- Jeff Gordon returning to championship form while winning his fourth Winston Cup title, and Dale Earnhardt Jr. and Kevin Harvick emerging as the stars of the future -- could change the season-long theme: safety.

 Armed with a new $2.8 billion TV package, NASCAR hoped this would be the year the series spread past its Southern roots and into new homes and demographics nationwide.

 It did that, in large part due to the attention -- albeit negative -- that Earnhardt's death brought.

 For a series already reeling from three on-track deaths in 2000, losing The Intimidator on Feb. 18 in the season-opening race was a crushing blow. Suddenly everyone wanted to know why the sport was unsafe and why the sanctioning body was so slow to react to the issue.

 Within days of Earnhardt's death, NASCAR revealed a seat belt had separated during the fatal crash. Then it launched a six-month, $1 million investigation that confirmed the finding.

 Teams and drivers had already started searching for their own ways to make racing safer when NASCAR finally joined the fold while straying from its decades-old stance that safety was the drivers' responsibility.

 Since Earnhardt's death, the sanctioning body has finally started to assume that role.

 Among the safety initiatives NASCAR introduced was making head and neck restraints mandatory and raising the minimum age limit from 16 to 18 for all competitors.

 NASCAR was also quick to react to concerns over pit-road safety following a November accident that injured three crew members. Beginning next season, anyone who goes over the wall during a race must wear a helmet.

 "Our efforts are sincere, our efforts are steadfast as we listen, search for answers and continue to communicate on advances for safety," Helton said. "We're all in this together. Together we need to make the sport bigger. Together we need to make the sport safer. Together we can make it stronger."

 In Formula One, no one was stronger this year than Schumacher, who captured nine of 17 races while winning his fourth series title. In doing so, he became the winningest driver in F1 history with 53 victories.

 His season overshadowed the stellar year his younger brother had. Ralf Schumacher won three times this year, started on the front row seven times and ended a career-high fourth in the season standings.

 Ralf did it in a year that started with tragedy: He was involved in a horrendous crash in the season-opener in Melbourne, Australia, that killed a track official and injured a dozen others.

 CART had its own tragedy.

 In a year of struggles for the globe-trotting series, things had finally started to look up in September.

 There was excitement over enthusiastic crowds at new races at new tracks in Germany and England, but the mood quickly changed when Zanardi -- one of CART's most popular and best-known drivers -- was so badly injured in a wreck that he had to have his legs amputated.

 It was another blow to the series, which had some of its most competitive racing in its 23 years but couldn't solve the problems that left it facing an uncertain future.

 Faced with losing all three of its engine suppliers and some of its biggest sponsors and teams -- CART co-founder Roger Penske is taking his two teams and principal sponsor Marlboro to the rival IRL -- the league is in serious trouble.

 "Nobody wants CART to succeed any more than me," said driver Kenny Brack, a former IRL champion. "There is no better series competition-wise in the world. I just hope they can solve all these problems and go on into the future."

 During the season, CART was forced to cancel a race in Brazil because of local politics and had to walk away from its inaugural event at Texas Motor Speedway two hours before the start because drivers were becoming dizzy and ill from the speeds and G Forces on the 11/2-mile tri-oval.

 The Texas situation eventually cost CART more than $3.5 million in a settlement over the cancellation of the race.

 The series also did its share to harass the IRL, which had its own problems this year.

 Despite charismatic champions in Scott Sharp, Greg Ray and Hornish, none has captured the public's attention and the series can't shake the perception that its a second-level racing organization.

 It didn't help matters when CART drivers returned to the Indianapolis 500 this year, with six of them joining NASCAR star Tony Stewart in the first seven places. The IRL's first finisher was a 45-year-old Chilean, Eliseo Salazar.

 Now, with CART champion Gil de Ferran and Indy 500 winner Helio Castroneves headed to the IRL with car owner Penske, others will probably follow. That means the IRL regulars could continue to find themselves on the outside looking in.

 For now, the IRL is celebrating Penske's defection and pointing to it as another indication that its form of American oval racing -- as opposed to CART's globe-hopping mixture of ovals, road courses and street courses -- will become more and more popular.

 "What better affirmation could there be than to have the most successful team in American motorsports choose the Indy Racing League as its competitive platform," said Tony George, IRL founder and Indianapolis Motor Speedway owner.