Road signs are meant to communicate information to drivers. These two practical signs travel with you, and do their job both simply and admirably.

Show your opposition to reckless driving, especially thoughtless tailgating, by exhibiting a yellow and black 5-inch by 6-inch safety decal in your rear window: "Caution-- Precious Cargo" speaks for itself. Protect the children by reminding negligent drivers of those who also use the public roads. Send $2 (check or money order) for each decal to LHW Enterprises Inc., 3221 Oliver St. NW, Washington D.C. 20015. 686-8829. Postage and handling are included.

Here's another one for the road -- or the airline terminal or even the sidewalks. If family or friends are traveling together in a car convoy, place an emblem on the rear window of each vehicle so other drivers won't cut in between you, possibly causing one car to miss a crucial highway exit. Orange and black "Travelling Together" emblems can also be applied to luggage that should be stacked together or even to clothing to keep track of members of a group. They're $3 for a package of two 4-inch-square emblems, $6 for a package of two 8-inch-square emblems and $8.50 for all four. Add 25 cents postage. Order from Peggy Rude, 3900 Military Rd. NW, Washington, D.C. 20015. 363-3900.