Sorry but all I can remember is a black and white film, a guy is driving at speed late at night on a freeway somewhere; suddenly we see that outside the passenger window a man is pressing his face against the glass! Really creepy, anyone have any idea what that film is?
Even though the details aren't exact to what you have said, this comes to mind.
In To Kill A Mockingbird, when Atticus leaves his car in the middle of dark and leaves his son in the car, he is encountered by Bob Ewell, the town drunk, who shoves his face on the window.
The scene of Bob Ewell staring into the window of a car: