Mark "Tex" Adams, practice mechanic in Florida for Joe Gibbs Racing's James Stewart was killed Thursday morning while helping a stranded motorist along Interstate 4 near Lake Helen, Fla., southwest of Daytona Beach.

According to the Florida Highway Patrol, Adams, 28, was assisting Tiffany Walters, who had run out of gas. At 4:30 a.m., The Orlando Sentinel said, Adams parked his Ford pickup behind Walters and stood adjacent to the driver's side door. The FHP said an SUV driven by Glen Ross II, 32, of Orlando, drifted onto the right shoulder of I-4 and struck the two vehicles and Adams, killing him. Charges are pending an investigation.

"I'm in disbelief as something so tragic could happen to you while helping someone else in need," Stewart said on his Twitter feed when he found out why his mechanic had not shown up for work. "I'm stunned because Tex was such a caring & doing for others person. My heart goes out to his family... He was always saying and doing funny stuff all the time and was a pleasure to be around."

Adams, of Carrolton, Texas, has also worked with Travis Pastrana and the Nitro Circus crew. On one infamous stunt he helped Pastrana try to fly a motorcycle when he bought an old airplane found in an attic and bolted it to a Suzuki RM250.

Stewart is scheduled to compete Saturday night in Round 4 of the Monster Energy AMA Supercross Series at Overstock.com Stadium in Oakland, Calif.