Oh, how I love the cutting edge technology of yore. In the 1930s, a scheme was proposed to identify hit-and-run drives by means of identification discs discharged by their cars as they speed away from the scene of the accident:
Suggested recently by a New Jersey lawyer, this scheme of bringing reckless drivers to justice makes use of a special device on the bumper which ejects small metal disks bearing the car’s license number and name of the driver, so that to learn the name of the culprit the victim needs only pick up a disk. Operation of the device will be automatic whenever a victim is struck.
From the Modern Mechanics Aug 1931 issue at Modern Mechanix blog: Link