( CNN ) -- A violent crash on a dirt track in New Jersey has claimed the life of race car driver Jason Leffler , a NASCAR veteran lauded by fellow racers as a fierce and versatile competitor . Leffler , 37 , died Wednesday , a little more than three months after returning to the world of short-track open-wheel racing after focusing on NASCAR circuits for more than a decade , according to his website . `` Sitting here in disbelief . ... All I can think about is Charlie , '' NASCAR racer Elliott Sadler said , referring to Leffler 's 5-year-old son . Leffler 's death at Bridgeport Speedway in Swedesboro , New Jersey , came during a qualifying race during the Night of Wings event , a 25-lap race for sprint cars equipped with stabilizing wings . Sprint cars are high-powered cars that usually run on dirt or paved oval tracks . Leffler was on the fourth turn of the preliminary heat when his car left the banked dirt track and flipped several times down the front straightaway , the South Jersey Times newspaper reported , citing witnesses . He had to be pulled from the vehicle , the newspaper said . `` NASCAR extends its thoughts , prayers and deepest sympathies to the family of Jason Leffler who passed away earlier this evening , '' NASCAR said Wednesday in a statement . `` For more than a decade , Jason was a fierce competitor in our sport and he will be missed . '' Condolences poured in from fellow drivers . `` Lost a good guy tonight in Jason Leffler . Prayers with your family ! '' racer Bobby Labonte said in a Twitter post . `` My thoughts and prayers are with Jason 's family and friends , '' driver Jeff Burton posted . `` Breaks my heart thinking of his little boy . '' Leffler began racing when was 12 years old , according to his website , and went on to win four U.S. Auto Club racing championships -- including three back-to-back championships from 1997 to 1999 -- and a place in the National Midget Auto Racing Hall of Fame . In 2000 , he finished 17th in the Indianapolis 500 . He switched his racing focus that same year to NASCAR 's Nationwide Series and later to the Camping World Truck Series in 2002 , according to his website . The Long Beach , California , native won two Nationwide Series races and finished in the top 10 in points for six consecutive years , according to his website . He decided to return to dirt racing for 2013 , planning to compete in up to 65 sprint car races . `` I 've got a lot of learning to do , '' he was quoted as saying on his website in March . `` It 's cool to be able to race 3 times a week and figure things out . '' Sprint car racing can be a dangerous sport , and accidents are not infrequent . A 22-year-old driver died three weeks ago in a crash at Bloomington Speedway in Monroe County , Indiana , CNN affiliate WTHR reported . In March , two spectators died when a car veered off-track at Marysville Raceway Park , outside Sacramento , California . In that incident , a car hit two tractor tires , sending it airborne and striking two spectators , a 68-year-old man and a 14-year-old boy . The driver was uninjured . In 2012 , a 20-year-old driver died when his sprint car hit the wall at Calistoga Speedway in Napa County , California , according to the Napa Valley Register . CNN 's Michael Pearson contributed to this report .
NEW : NASCAR veteran Jason Leffler had just returned to dirt-track racing . He died Wednesday in a crash at a New Jersey dirt track . The Associated Press contributed to this report. `` Lost a good guy tonight , '' racer Bobby Labonte tweets .