DON'T BLINK, or you'll miss it: U.S. 66, the Route 66 of song and television, is being, as the bureaucrats might put it, phased toward termination. Route 66 once symbolized for Americans a kind of escape, of farmers from the Dust Bowl and of adventure-seekers from the small towns of the Midwest, all going to the promised land of California. From Oklahoma westward it followed a route blazed by a camel caravan in 1857 and paralleled the also fabled Atchison, Topeka & Santa Fe. U.S. 66 was plotted in 1926, at a time when few Americans thought of traveling more than a few dozen miles by car. It spanned most of a continent, from Michigan Avenue near Chicago's lake front (within sight of the Santa Fe's headquarters) to Los Angeles' Pacific Coast Highway.

U.S. 66 is now, thanks to the logic of highway route numberers, Interstates 55, 44, 40, 15 and 10. With those interstate routes completed, after endless delays promoted by gas-station owners in Arizona desert towns, the folks at the American Association of State Highway and Transportation Officials, who number U.S. routes, saw no reason not to abolish U.S. 66. They were operating, as highway numberers seem to do, according to a certain orderly logic. East-west highways have odd numbers, north-south highways even ones. Interstate numbers get higher as you go east and north, U.S. numbers go higher as you go south and west. Thus while U.S. 66 goes to the Southwest of the country, Interstate 66, which extends from the Kennedy Center to Front Royal, is up here next to the Northeast.

Unfortunately, there's not too much room for poetry or common sense in the highway numberers' logic. Moreover, the numberers can't bear to see something that looks incomplete on the map. That's why the Capital Beltway has two numbers. From Springfield west and north to Beltsville, it's Interstate 495; east of that, it's Interstate 95. The result: lots of confusion among local residents and tourists.

Perhaps it's too much to expect American highway numberers to duplicate for the whole nation the romance evoked by the Storm King Highway (just north of West Point, N.Y.) or Going-to-the- Sun Highway (hacked out of mountainsides in Montana's Glacier National Park). But did they have to abolish U.S. 66? And was it really helpful to give half the Beltway one number and half the other?