NASCAR

Marcos Ambrose has informed Richard Petty Motorsports he will leave NASCAR at the end of this season and return to his native Australia.

Tony Stewart says the death of Kevin Ward Jr. will "affect my life forever" as he returned to the track for the first time since his car struck and killed the fellow driver during a sprint-car race in New York.

NASCAR has added a new rule telling drivers to not approach the track or moving vehicles after accidents. The rule comes less than a week after a driver was struck and killed during a dirt-track race at a small New York track.

NASCAR president Mike Helton says there is no animosity from the governing body toward the recently formed nine-team Race Team Alliance that will collaborate on initiatives and issues facing the sport.

The top nine teams in NASCAR have formed the Race Team Alliance to collaborate as a group on initiatives and issues facing their sport.

Jimmie Johnson's run at another Sprint Cup title is on and could lead to NASCAR history.

Sprint Cup points leader Jeff Gordon cut short his practice Saturday because of back spasms and the No. 24 team has Regan Smith on standby should the four-time champion not be able to run the Coca-Cola 600.

NASCAR's most popular driver has certified that Charles Barkley is "not turrible" behind the wheel.

Juan Pablo Montoya will make a two-race return to NASCAR this season, driving for Team Penske in the Brickyard 400 and at Michigan International Speedway.

NASCAR team owner Gene Haas says he plans to field an American-based Formula One racing series team within the next two years.