WILKINSBURG, Pa. -- Pittsburgh police have been searching for a driver who sped away from a traffic stop, hitting a passenger after that man got out of the vehicle and tried to run away.

Police have not identified the vehicle's passenger, who refused medical treatment shortly after the traffic stop at 1 a.m. Tuesday along Brushton and Hamilton avenues in Homewood.

Police continued to chase the driver who crashed his vehicle a short time later over a hillside along Clark Street in Wilkinsburg. Police said the driver got out and ran away, and they've been unable to find him.

Police were using search dogs to look for the driver. So far, no charges have been filed and no arrests have been made.

Police haven't said why they stopped the car in the first place.