Hickman died in an accident during a practice session at the second Milwaukee Mile race of the 1982 season, the Tony Bettenhausen 200 at Wisconsin State Fair Park.
Published reports indicated that CART observers and technical personnel determined that a stuck throttle was the cause of the accident.
Driving a 1981 March 81C-Cosworth for Hoffman racing sponsored by Stroh's Beer, his car slammed into the concrete wall in the first turn of the one-mile (1.6 km) oval.
Dr. Steve Olvey, medical director for CART, said Hickman died of head injuries.
He was survived by his wife, Lynda, and two children, Ashley and James Franklin III.