Dear Dr. Gridlock:

HELP! Isn't it time to reevaluate whether single drivers should have access to the HOV lanes at the 14th Street bridge?

The law that allowed conventional traffic to get access to the HOV lanes at a ramp at the Pentagon has created a horrendous traffic jam as single drivers move out of the I-395 regular lanes in their vain attempts to get across the bridge.

As soon as we come around the corner at the Pentagon, everything stops dead. As we creep across the bridge in the jammed HOV lanes, we can see traffic fairly zipping along in the conventional lanes! Yet the ramp that lets them into our lanes is only one-way: we can't slide over to the conventional lanes.

I've been in a car pool for five years, and for the last year have watched this situation deteriorate. We normally cross the bridge between 8:05 and 8:15 a.m.

Is there any help for us? Can't something be done to limit access to the HOV lanes by single drivers? Can't the District do something to allow more cars through the lights at C Street and Independence Avenue at the other side of the bridge? HELP! POLLY BEDNASH Fairfax

Your letter prompts Dr. Gridlock, and Virginia highway officials, to look at this situation again. But we must take a careful look, because an enormous number of motorists are benefiting from access to the HOV lanes at the Pentagon without adversely affecting congestion in the HOV lanes -- at least according to 1990 statistics.

Quick background: Virginia, the federal government and the District of Columbia agreed in 1987 to open Ramp G, near the Pentagon, to all traffic. That ramp allows access from the conventional northbound Interstate 395 lanes into the two-lane, barrier-protected, High Occupancy Vehicle corridor. The agreement was reached because the reconstruction of the Southeast-Southwest Freeway (I-395) in the District was constricting traffic flow across the 14th Street bridge in the conventional lanes.

Under the agreement, the ramp is to remain open to all traffic until the Southeast-Southwest Freeway project is completed, or until congestion in the HOV lanes becomes unacceptable.

The Southeast-Southwest Freeway project will last at least another three years. So, that leaves us looking at the level of congestion in the HOV lanes. According to the latest Virginia traffic count, taken in 1990, 3,200 vehicles were crossing the 14th Street bridge via the HOV lanes in the peak morning rush hour. The optimum count, from the state's point of view, is 3,000 vehicles. The state views the difference as not very significant.

The District's traffic count, taken this year, shows 5,600 vehicles crossing the 14th Street bridge in the two HOV lanes during the morning rush hour period (6:30 to 9 a.m.) vs. 16,500 during the same time in the four conventional lanes. That suggests significantly more congestion in the conventional lanes.

Virginia officials had not scheduled another traffic count until next spring. But as a result of your inquiry, the state is going to do another traffic count in September, said Mary Anne Reynolds, a spokeswoman for the Virginia Department of Transportation.

Also as the result of your inquiry, the District government sent a transportation official across the 14th Street bridge during morning rush hour. He reported no delays at all. Part of the deterioration you may have been seeing is that the two right lanes of the Southeast-Southwest Freeway were closed for about five months earlier this year. That probably prompted many more motorists to use the HOV lanes to cross the Potomac because the HOV lanes exit into the left lane of the Southeast-Southwest Freeway.

The District government believes it has timed its lights at C Street NW and Independence Avenue NW correctly, said Department of Public Works spokeswoman Schanolia Barnes. Already, the lights allow significantly more green time to inbound commuters than to other traffic, she said.

But the city will take another look at the timing of the lights during the time you have been having problems, Barnes said.

After Ramp G was opened to all traffic in 1987, Dr. Gridlock was deluged with letters from grateful commuters who said this move had shaved up to 30 minutes off their inbound commute and basically had made their life worth living.

Virginia transportation spokeswoman Reynolds said her department had received no other complaint like yours, Ms. Bednash. Still, it is good to take another look at the traffic count to be sure sufficient incentives remain in place to encourage car pooling. But it should be a very careful look. Time of the Signs

Dear Dr. Gridlock:

My wife and I were on the HOV lanes of I-395 south from Washington to the Newington-Fort Belvoir exit. The date was June 19 and the time was 7:15 p.m. As we came to the Edsall Road exit, there was an electronic overhead sign that told us there was congestion in 3 1/2 miles (around the Newington exit).

Three other times we had seen the same sign warning of congestion, and when we arrived at the point, there was no congestion. So we took a chance this day and sure enough, there was no congestion.

My question is this: Why did officials spend our tax dollars on a system that is not attended? I could have heeded the advice on the sign, exited at Springfield, and added another 15-20 minutes of time using the back roads to avoid the congestion that did not exist. JACK WOLFE Springfield

I know the frustration. It has happened to many of us: the warnings of congestion that prove to be false.

In this instance, the state's cameras that normally see down I-95 to the Newington interchange are out of commission because of the construction of the HOV lanes south of Springfield. So the state's traffic control center had to rely on reports from the field. The all-clear report doesn't come in until the congestion is cleared. Here, the state put the congestion sign on at 6:11 p.m. and took it off at 7:12 p.m., according to logs kept at the traffic control center.

If you passed the sign at exactly 7:15 p.m., depending on whose watch was correct, you must have passed just as the warning was being removed, Mr. Wolfe. That means everyone in a 3 1/2-mile corridor between you and the congestion also got that false message.

I'm not sure what the solution is, but it seems these signs -- part of a $22 million project designed to be help motorists -- too often carry outdated information.

Hoping to See the Light

Dear Dr. Gridlock:

I'm a retired person, and trying to walk around McLean is almost suicidal.

How do we get a traffic light, or at least some kind of sign for pedestrian crossing, at the intersection of Beverly Road and Fleetwood Road, or one of the nearby intersections? This would allow us to walk to the Safeway, Rite Aid and other stores without getting killed. STANLEY W. OZARK McLean

The Virginia Department of Transportation will conduct a study of any traffic light request, spokeswoman Stacy Marbert said. Officials will see if there is a recent analysis on file, and if not, will look at traffic volume and number of accidents to see if a traffic light, or other markings, are warranted. They may not grant your request, but they will respond giving their logic, Marbert said.

Write to Loren Epton, Traffic Engineering, Virginia Department of Transportation, 3975 Fair Ridge Drive, Fairfax, Va., 22033.

Limos Park Free at Airport

Dear Dr. Gridlock:

I've noticed that National Airport now has parking for limos. This parking, near the Metro station, is located in a very convenient spot. Yet, while private cars have to pay for parking at the airport and taxis have to pay a fee, a policeman at National told me that the limo parking is free. This does not seem equitable. H.J. ROSENBAUM Alexandria

You probably noticed the limos mingling with the buses in front of the main terminal too. This is because National regards limousines and buses as commercial vehicles for hire, and wants to move them in and out of the airport as fast as possible. That's why they get convenient parking and no fees. Cabs are commercial vehicles too, of course, but there are so many of them (5,000 a day), that fees are charged to pay for the dispatching facility and personnel.

Motorists like you and me have to pay to park because that provides the money to operate the lots, an airport spokeswoman, Tara Hamilton, said.

There are 4,700 parking spaces at National, although that number fluctuates somewhat because the airport facilities are being reconstructed (completion date: 1999). A multistory garage, with 2,100 more spaces is scheduled to open by the end of this year, and eventually, the plan is for a total of 8,000 spaces.

You can check on which lots are open on the day you want to park, and what the rates are, by calling 703-271-4311. That number is updated constantly as lots fill.

What Coins in the Meter?

Dear Dr. Gridlock:

One thing that frustrates motorists, including myself, in downtown Washington is that parking meters accept only quarters, and no other coins. Is there some reason for this?

It would sure be easier on motorists if the meters were modified to accept nickels and dimes, and the city would make more money too. TOMBONG SAIDY Washington

You would think the city would do that. I can remember when we were able to use not only nickels and dimes, but (har-har) pennies too. The city has this explanation for why the parking meters now accept quarters only: The use of many different kinds of coins makes the machines wear out faster. This according to Schanolia Barnes, spokeswoman for the D.C. Department of Public Works.

Dr. Gridlock checked with our sister city, Baltimore, to see what they do, and it's basically the same. Quarters only on the downtown meters. The timing mechanism is small and delicate and was too easily sent akilter by use of coins of various sizes. People were complaining that the meters weren't keeping accurate time, so the city converted to simpler, quarters-only meters, said Department of Transportation spokeswoman, Vanessa Collins.

Asked why meters used to take many type coins without such problems, she said, "Guess they don't make them like they used to."

Still, aren't there meters in other areas of the country that take nickels, dimes and quarters and aren't a maintenance problem?

Wilson Bridge Blues

Dear Dr. Gridlock:

I try to avoid the Beltway as much as possible, but on June 6 found myself in Prince George's County, headed for the Woodrow Wilson Bridge. I was delighted at seeing an electronic overhead sign announce that the bridge would open at noon. I glanced at my watch and saw that I had plenty of time to cross before the bridge would open.

After passing all exits and getting on the bridge itself, I was confronted by a span already opening. The time was 11:52 a.m.

If there had been no warning sign, I would have considered my plight just fate. Since there had been a warning sign, which had incorrect information, I considered my plight to be the result of sloppiness in operations.

If there had been a question about the exact time of opening, the time shouldn't have been presented in such a precise fashion. A message indicating that it would open between 11:30 and noon would have warned me to change my route.

I hope you can convince those who control the Beltway message boards that bad information is worse than no information. MARK M. MACOMBER Camp Springs

Ah, that bridge. This is what can happen when you have three jurisdictions controlling it. A little explanation: The District controls the tower operator, who is supposed to notify Virginia of bridge openings. Virginia then notifies Maryland. Maryland then puts up the information, except on several Maryland signs approaching the bridge that are actually controlled by Virginia. Got this so far?

On June 6, Virginia notified Maryland at 5:58 a.m. that the bridge would be raised at noon, according to Maryland logs. Maryland put up its warning at 11:30 a.m., one-half hour in advance, as usual, said Al Marquess, who runs the traffic operations center for Montgomery and Prince George's counties. When the bridge was actually raised is a matter for the District government to answer, he said.

The District checked its logs, and lo, the bridge was opened at precisely 12:01 p.m. on June 6, according to a Department of Public Works spokeswoman. It was not opened at 11:52 a.m., she said. Never mind what you saw, Mr. Macomber. It didn't happen, according to the officials.

I don't know where to take this from here other than to invite others to write in if you've had similar observations. If there is a pattern here, it may be easier to look at a fix.

Dr. Gridlock appears in this section each Thursday to explore local transportation matters. You can suggest topics by writing (please don't phone) to DR. GRIDLOCK, The Washington Post, 1150 15th Street NW, Washington, D.C., 20071.