Michael Theodore Barnes, 44, of Pasadena was booked on assault with a deadly weapon following the alleged attack, according to Pasadena police officials and Los Angeles County booking records.
The violent encounter unfolded about 7:15 p.m. at an ARCO station at Walnut Street and Los Robles Avenue, Pasadena police Sgt. Bobby Crees said.
Barnes became involved in a road-rage dispute with the victim, a 43-year-old Pasadena man, he said. Both drivers pulled into the gas station and got out of their cars.
Barnes brandished a metal anti-theft steering wheel lock, Crees said. The victim pulled a machete.
The victim then disarmed himself, laying the machete on the ground, according to Lt. John Mercado. The suspect used the opportunity to strike the victim in the head with the metal device.
The victim was taken to a hospital with a gash to his head, police said. Officers arrested Barnes at the scene.
According to county booking records, Barnes was being held in lieu of $30,000 bail pending his initial court appearance.