Police Chief James Mann told KDKA that Stevenson was involved in a road rage incident shortly after 7:15 p.m. Wednesday along Merchant Street between a car driven by Charles Hawk and his son, Ronald Hawk.
At one point, Mann said Stevenson turned right onto Glenwood, a one-way street, and was driving the wrong way. He tried to turn around and Hawk's car blocked him in.
Mann said Hawk got out of the car and started walking toward Stevenson, who then accelerated and struck Hawk.
According to witnesses, Hawk rolled onto the hood and fell off when he lost his grip. Mann said he rolled under the car.
Police said Hawk suffered serious injuries, including a broken ankle and cuts to his head.
Witnesses said Stevenson drove recklessly before his car struck two other cars, injuring the two teens riding with him. A man, whose daughter lives near the scene, said a Good Samaritan who witnessed everything followed the actors and called the police.
A preliminary hearing is set for March 11.