He struggled early in the Busch season, but managed to qualify in his first attempt at Winston Cup during the DirecTV 500 at Texas Motor Speedway on April 2.

Lee Petty, Adam's great-grandfather, and 3-time NASCAR Champion, lived to see his Winston Cup debut, but died just three days later.

On May 12, 2000, in a practice session for the Busch 200 race[1] at New Hampshire Motor Speedway, which would have been his 48th career Busch Series start, Petty's throttle had stuck wide open going into the third turn of the track, causing the car to hit the outside wall virtually head on, killing Adam instantly as he developed a basilar skull fracture.

Petty's death, along with 1998 Winston Cup Rookie of the Year Kenny Irwin Jr.'s in the same corner at the same track eight weeks later,[3] led NASCAR to mandate the use of a kill switch on the steering wheel and the adoption of the Whelen Modified Tour restrictor plate for the September Cup race; which was abandoned following the race, in where Jeff Burton led all the laps to win.

Both adjustments addressed the cause of the deadly accidents, with the exception of course of the basilar skull fractures suffered by both drivers.

At Texas Motor Speedway, Truck Series driver Tony Roper died on October 14, 2000, of a similar skull fracture.

Use of the HANS or Hutchens device (designed to prevent the rapid-deceleration head-and-neck movements associated with the injuries and skull fractures associated with the Petty, Irwin, Jr., and Roper deaths) was mandated by NASCAR in October 2001,[4] following the later deaths of seven-time Winston Cup champion Dale Earnhardt on the last lap of the Daytona 500 on February 18, 2001 and ARCA RE/MAX Series competitor Blaise Alexander during ARCA EasyCare 100 at Charlotte Motor Speedway on October 4, 2001, both of whom died from the same fatal skull injuries.

NASCAR also adopted the SAFER barriers in 2002; drivers had requested installation of soft walls prior to the September New Hampshire Cup race.

44 Hot Wheels-sponsored Pontiac Grand Prix Winston Cup car at the time of his son's fatal crash at New Hampshire, chose to take over Adam's No.