Test Your Road Sign I.Q. . . . by Joseph D. Younger, originally appeared in Car & Travel then was picked up by the Reader's Digest. I ordered reprints from the Digest.

It focuses on driving the Interstates and what the colors, numbers, signs, of that system mean. It is the handiest four pages I've ever run into. And it is free.

You need to send a stamped, self addressed envelope and request for Road Sign I.Q. to: