Dear Dr. Gridlock:

As I drive the Beltway in Montgomery County, I notice a number of concrete walls at various points along both sides of the roadway. I assume they are for noise reduction. I can understand this where the Beltway is immediately adjacent to houses, but there seem to be a number of locations where there is nothing behind the walls but wooded areas.

As a driver, I find them ugly and boring to look at. When they are on both sides of the Beltway, they give me a claustrophobic feeling like I'm driving in a tunnel.

I would like to know how much these walls are costing us taxpayers, and whether or not there are plans to encircle the entire Beltway with these unsightly barriers. MICHAEL HOYT Silver Spring

We all have our roadway problems, don't we? This one seems worth getting into because it's obvious a lot of money has been spent on these things.

Noise barriers are a phenomenon of the last two decades, as highway engineers have paid more attention to the impact of interstate highway traffic noise on adjacent neighborhoods.

A lot of folks bought homes before our local interstates were built, or widened, and now are finding the constant din overwhelming. Mothers can't be heard calling children. Conversations can't be heard. This isn't like living under a flight path, with frequent interruptions. This is more constant.

So far, about 90 percent of the money for these shields has been supplied by the federal government for use alongside interstate highways in heavily populated areas. That money is drying up, though, and state and local officials, with their own revenue problems, aren't rushing forward with money.

There are no plans to encircle the Capital Beltway with these barriers; instead they are being installed in spots when money becomes available and as residents along interstates make their needs known. Some communities have been waiting for years. A number of projects have been approved on the Beltway in Maryland, and are awaiting funding.

Barriers are not cheap. They can cost $23 to $27 a square foot and can be up to 26 feet high; that means more than $1 million a mile, or enough to add another lane of highway somewhere, or to make badly needed fixes to existing roads.

If you're seeing noise barriers apparently shielding nothing but trees, Mr. Hoyt, here are a couple of possible explanations: (1) there is a residential community right behind the trees (yet out of view), or (2) the barriers have extended 400 feet or so beyond residences to help contain the noise.

Neighborhoods need to meet certain criteria to be eligible for the barriers. The noise level has to be sufficiently high over a 24-hour period, and most of the homes have to have been built before the interstate was constructed, realigned or widened.

Residents along Interstate 66 in Virginia, outside the Beltway, found noise reaching the intolerable as traffic counts climbed to 160,000 vehicles a day. The residents lobbied for years for noise barriers, and finally got approval after a public hearing in which one resident played a tape recording of the traffic noise while another tried to speak to Virginia officials. No one could hear the speaker, and the officials got the message.

Rep. Frank R. Wolf (R-Va.), working with the state transportation secretary, John G. Milliken, obtained $8 million in federal funds as a "demonstration project" for noise barriers. They will be installed in spots on both sides of I-66 along a 7.7-mile stretch between Gallows Road and Route 50.

Several projects around the Maryland Beltway have been approved and are awaiting funding.

True, noise barriers are not attractive. Some have proposed turning them over to artists. Probably the less distracting they are, the better, even if they are boring. Hope this helps.

Metro's Done Deal in Arlington

Dear Dr. Gridlock:

Arlington County has an unusual response to the success of the area's Metro discount program. They're ending it.

I'd have asked county officials not to, but they held one of the least publicized public hearings I've ever seen in Arlington. Perhaps that explains why, according to local press accounts, only two people showed up. I ride Metrobus and Metrorail in Arlington on a daily basis, but never saw any notice of the hearing.

Of more personal interest, are only the rail discounts being ended, or can we also say goodbye to round-trip transfers and the Arlington Flash Pass? Is there anything left for Arlingtonians to do that might save the discounts, or is this a done deal. Can you get someone from Arlington to comment? GREGG WIGGINS Arlington

Yes. Mary Margaret Whipple, an Arlington County Board member and chairman of the Metro board, says the rail discounts will be ended as of Nov. 10 because the subsidy was becoming too expensive weighed against other needs. Arlington spent $400,000 in subsidy money during the year or so of the test. That allowed a rider to get on and off Metrorail in Arlington for a 60-cent fare, a savings of 25 cents.

The purpose was to introduce more people to Metrorail, and ridership did go up during the test period. At the same time, though, an enormous number of trips began or ended at the Fashion Center at Pentagon City, and it wasn't quite clear how much new ridership was generated by the center, rather than by the discounts.

Only the rail subsidy is being ended. The other public transit discounts for Arlingtonians remain in place. And yes, it is a done deal.

Whipple and Metro spokeswoman Beverly Silverberg say that the public hearings on these matters were advertised in newspapers as usual.

Any Arlington resident can get on a mailing list for County Board agendas by calling 703-358-3130. Those wishing advance notice of Metro public hearings can get on that mailing list by writing to the Metro Board secretary, 600 Fifth St. NW, Washington, D.C. 20001.

20-Rider Backup for Farecards

Dear Dr. Gridlock:

Here's a form of gridlock that hasn't been reported in your column. It occurs when Metro employees decide to empty the Farecard machines at the height of rush hour. Twice I saw the servicing of Farecard machines at Union Station at about 8 a.m. The lines to the three functioning Farecard machines each had at least 20 people.

If Metro wants to convince people that public transportation is better than fighting the traffic, they should not go out of their way to create unnecessary traffic jams in Metro stations. RICHARD N. LIEBERMAN Baltimore

Metro services its Farecard machines regularly, to restock Farecards, remove money and supply change as needed.

The job is done by specialists, not the regular station attendants, and takes all day (Metro now has 63 stations), Silverberg said. The work is not done late at night, after the stations close, because of overtime and security costs. "I'm told it takes under two minutes to do one machine," Silverberg said.

Does this answer fit with what you're observing?

Protecting Nature's Creatures

Dear Dr. Gridlock:

Every year thousands of innocent animals are cruelly crushed to death on the nation's highways, through no fault of their own. They cannot read signs.

However, there is a viable alternative. Some firms have invented an ultrasonic warning device that can be attached to car bumpers. These are wind-powered and require no electric current. Catalogues offer them for less than $5 apiece.

Let emergency vehicles (ambulances, fire trucks, police cars) take the lead in installing these devices, since urgency is required of them. Civic groups could even assist in fund-raising.

Shall we simply close our eyes and play ostrich? God's creatures surely deserve a better fate. BARRY LEE COYNE Arlington

This letter prompted a further conversation with Mr. Coyne to see where you could get these devices. He provided the name of the supplier: Carol Wright Gifts, Box 8503, Lincoln, Neb., 68544. It is called an animal repeller and costs $3.95.

Dr. Gridlock ordered one. It is a small device that is supposed to be affixed to the outside of the car and works when air rushing into it is said to emit an ultrasonic sound that drives animals away. One question is how do you know the thing actually works if you never hit an animal?

Asked about this, American Automobile Association spokesman Rob Krebs said his organization has no knowledge of the Carol Wright product, but that AAA sells its own animal repeller, possibly more durable and also using ultrasonic waves, for about $20. They are available to anyone by going to an AAA service center, or calling 703-AAA-8200 for the name of the center nearest you.

"People have been coming into our centers claiming they {the devices} are fantastic," Krebs said. "I guess the evidence is that Park Police and rangers use them in game preserves. One of our secretaries hit a deer and then got a repeller and hasn't had a problem since."

The sentiment here is noble. Anybody else have any experience with these devices?

Watch Out for Those Goblins

Of all the pedestrians who are killed or injured by cars, those in the highest-risk group are children ages 5 to 9 who cross the street between parked cars at night. This is according to a study by the American Automobile Association. An advisory to parents of trick-or-treaters: children should cross streets only at corners, and hopefully be accompanied by an adult. Drivers, obviously, want to be especially attentive on Halloween.

Bus Shelter Courtesy of the Boss

Thomson M. Hirst, a commercial developer in Northern Virginia, noticed a woman standing in the rain waiting for a Metrobus at the entrance to his Lake Fairfax Business Center office in Reston, and decided to do something about it. He funded and installed a badly needed bus shelter, and made sure a bus schedule is posted there.

"Government help is fine, but it is sometimes more efficient for individuals to just fix the problem," Hirst said at a dedication this month.

The business center provides employment for 3,000. Several companies, including Hirst's Mason Hirst Co., are working on a plan to encourage employees to ride Metro, hoping that will form a core to provide express bus service to the nearest Metro station.

This sounds good. Any small steps to relieve gridlock are welcomed.

Write to DR. GRIDLOCK, The Washington Post, 1150 15th St. NW, Washington, D.C. 20071. Please include your full name, address and day and evening phone numbers.