The crash occurred shortly after midnight at the intersection of East Somerset and North Swanson streets.
Police say the driver of a car was backing up his vehicle near the intersection when he slammed into a parked pick-up truck.
The car continued on the sidewalk and struck a 20-year-old male riding a bicycle.
The impact of the crash sent the bicyclist onto the street.
The driver then abandoned the vehicle and fled on foot.
Medics transported the bicyclist to Temple University Hospital where he is in critical condition with a serious head injury.
The crash remains under investigation.