The March, 1936 ish of Science and Mechanics featured this dubious DIY project to keep street urchins from riding on your horseless carriage's bumpers: electrocute 'em! Didn't I see this in a Little Rascals short?
IF your auto is pestered by hitchers-on, here is a good cure. Fit a Ford coil with a piece of chain which will drag along the ground (but must not touch the car), and ground the other end of the coil to the car. Complete circuit as shown, and close switch for results–Rocco Conte.