It was just before 3 a.m. on Saturday, when officers responded to the 900 block of Watts Street in North Philadelphia.
Police say the driver hit a 25-year-old man and then just kept going.
"Turn yourself in, don't hurt nobody, and do the right thing," said Cecil Bosman of Francisville.
The victim was taken to the hospital in critical condition. Police say the man suffered a skull fracture and internal bleeding.
"It was pretty scary honestly because that could have been anybody. It could have been me. I ride around here late at night too," said Jon Glenn of Frankford.
Police are looking for the driver of the white vehicle, possibly a Jeep. It was last seen speeding southbound on Watts Street towards Parrish Street.
"I'm not surprised that somebody was speeding down and got hit, honestly. I almost got hit a couple times on my skateboard. A guy broke my skateboard by running over it and I had to jump out of the way," said Glenn.
Police are asking anyone with information about this incident or the identity of the driver to contact them.