Congratulations apparently are in order to Virginia and Maryland highway officials for responding to reader complaints about the signs on the Beltway. Motorists pointed out in this column a year ago how confusing it is to have a Beltway that is part Interstate 495 and part Interstate 95. The Beltway segment from Springfield east around to College Park was designated I-95 by local and national officials to keep I-95 continuous from Florida to Maine. But that doesn't help visitors new to the area, who sometimes wonder whether they are on the Beltway, I-495, I-95 or what.

Now Maryland and Virginia highway chiefs Hal Kasoff and Ray Pethel, after studying the situation, have agreed with the concerns. With support from federal officials, they have announced that their departments will place signs reading "Capital Beltway" atop major signs around the Beltway, as well as stand-alone signs around the Beltway featuring a logo of the Capitol. Details are to be worked out at a meeting at the end of this month, and the signs should go up not long after that, according to Virginia highway spokeswoman Marianne Pastor. Public officials can't fix all our traffic woes, but they can take steps like this to show they care. That's gratifying. Yield, Varlet! Dear Dr. Gridlock:

When did "Yield" cease to mean give way to drivers on the road you are trying to enter, even if it means stopping? I am constantly annoyed by inconsiderate drivers who pull out dangerously, often without even looking. If you're driving on a four-lane road and see a car ahead about to enter the highway, the courteous thing is to switch into the left lane to give {that person} room. But if there is traffic on your left, you can't switch lanes. When you are going 60 and some fool entering the highway pulls right in front of you going 35, it's a dangerous situation and it ought to stop and be subjected to stronger police enforcement. JAY LOUNSBURY Dunkirk, Md.

You've pointed out one of the most annoying situations on the road, and one of the causes of gridlock. When someone pulls out in front of us going one mile an hour, we are left to wonder what exists between that driver's ears. Psychiatrists cite these kind of drivers as examples of narcissistic behavior. That is, they are so absorbed with themselves they haven't got a clue what is going on around them. On the road, these people are dangerous, as you point out. One can only hope that police will watch out for them and go get them. (By the by, has anyone ever seen that happen?)

Open Up in There, Metro Dear Dr. Gridlock:

I am not a regular user of the Metro system, but I thought it would be a perfect way to get to National Airport this past Saturday to catch a 7:49 a.m. flight. I leisurely drove to the Huntington Station, arriving at about 7 a.m., and parked on the lower level. I discovered the doors to the elevator lobby were locked, and looked around for another way in. It never occurred to me that the station was closed.

I found a stairway and went up a flight. This led to an open parking lot with elevators accessible from the outside. However, when I pushed the button nothing happened. So I ran up another flight, found escalators in front of me, ran down the escalator to the station and only then did I find a sign that told me the station did not open until 8 a.m.! This is a long trip when you're carrying a suitcase and have a plane to catch.

Please ask Metro officials to post signs on all entrances with the station hours. It would have saved me valuable minutes. CYNTHIA A. CELICH Alexandria P.S. I made my flight.

Metro spokeswoman Beverly Silverberg agrees with you. "What we need is signs at all entrances," she said.

"We will make a survey and see how we can be more specific. Meanwhile, our sign people will put up more signs at Huntington.

"We don't want to take our infrequent riders for granted. We appreciate this reader bringing this to our attention; it helps to have extra eyes and ears out there."

The Metro rail system opens at 6 a.m. on weekdays and at 8 a.m. on Saturdays and 10 a.m. on Sundays.

Fore-and-Aft Bus Numbers Dear Dr. Gridlock:

After a very long campaign, Bill Gold, who used to write the District Line column for The Washington Post, declared "victory" when the bus officials agreed to have buses show the bus line number in the rear window of every bus.

This helped riders identify the desired bus from behind the bus and not run for a bus only to discover that one had chased after the wrong bus. For a time this was fairly well observed. Bus drivers placed the appropriate cardboard or plastic line number in the rear window at the start of a run and could easily change the sign when necessary.

The practice seems to have fallen apart and I just about never see any indication at the rear of what line a bus is on. This was a great convenience and seems easily remediable. Can you help?

What a good letter. You're walking toward a bus stop and a bus passes by. Of course, there's no way to see the front of the bus by the time you notice it passing by. Should you run to the bus stop? The number at the back would tell you whether to run. Makes plenty of sense.

Metro officials say they started requiring bus drivers to post numbers at the back of the bus in 1974. What happened over the years is that riders, usually teen-agers, would change the numbers, make offensive words out of them, or pull them down altogether, according to Metro spokeswoman Marilyn Dicus. Metro got complaints, and eventually, she said, people came to rely on the front of the bus as the primary source of information because no one could trust the sign at the back of the bus. So a few years ago, Metro let bus drivers decide whether they wanted to post signs at the rear. Dicus said she has no idea how many bus drivers still do this.

So how come Metro can't put an encased electronic sign at the back, just like the one at the front? Beverly Silverberg, Metro's chief spokeswoman, says Metro has 1,500 buses, and to do that would be too expensive. "We've looked at this several times," she said. "I'll go back to the head of bus services to see if there is any new technology," that would make this possible.

Let's hope she comes back with good news. Does anybody else feel strongly about this? If so, we'll pass along the letters to Metro.

Dr. Gridlock appears in this section each Friday to explore what makes it difficult to get around on roads, from misleading signs to parking problems to chronic bottlenecks. We'll try to find out why bad situations exist and what is being done about them. You can suggest problems by writing to GRIDLOCK, c/o The Washington Post, 1150 15th St. NW, Washington, D.C. 20071. Please include your full name, address and day and evening phone numbers.