It happened on the southbound lanes of the highway near Exit 9 in Tinicum Township.
Around 5:30 p.m. police found the driver, 31-year-old Clifford Douby, inside a crashed black Honda on the southbound lanes of the highway.
Police say Douby sustained a gunshot wound and was found dead at the scene.
Further circumstances surrounding the shooting are still unknown at this time, but police do believe that the shooter was inside another unknown vehicle.
Investigators are asking anyone in the area of Exit 9 on I-95 to come forward with information by calling 484-840-1000.
Police say they working around the clock to solve this case.
"Our criminal investigation unit members are working extensively, following up on all info received pertaining to this incident. I assure you that our department is doing everything possible to arrest this person or persons responsible," said Trooper Jessica Tobin with the Pennsylvania State Police.