In the Dec. 19 Dr. Gridlock column, reader Alfred Regnery of Alexandria said this:

"The Washington & Old Dominion (W & OD) trail is a nice bike path, but it is a luxury we can no longer afford. Local officials should seriously consider buying the path and turning it into a rail line again."

Mr. Regnery reasoned that a new rail line would serve a number of communities (Arlandria, Shirlington, Columbia Pike, Reston, Sterling) that are not now served by a Metro line.

Some responses:

Dear Dr. Gridlock:

If the trail is entirely given over to commuters, it would be a huge disservice to the walkers, joggers and bicyclists who enjoy the recreational advantage.

People need parks and natural scenery. Forget the rails: too expensive and unnecessary. Put trams on the trail with radial tires. Run them during rush hours and leave them in shelters at other times while the trail returns to its original purpose.

William Smith

Fairfax County

Kudos for a creative idea, Mr. Smith.

Dear Dr. Gridlock:

The W & OD is not just a nice bike path, it is used by thousands of walkers, joggers, bikers, skaters, horseback riders, mothers and fathers pushing babies in strollers and, yes, commuters on their way to and from work.

The proposed Metro extension from West Falls Church to beyond Dulles airport is a better alternative; for much of its length it would run along an already-designated right of way that is not used for any other purpose.

I agree with Mr. Regnery regarding smart growth, but we can work toward that goal without depriving Northern Virginia of one of its most important recreational and alternate transportation resources.

Robert Kwartin

Vienna

Dear Dr. Gridlock:

I was laughing so hard after reading the Alfred Regnery proposal to do away with the W & OD trail and build a railroad. I told my wife you must have written that letter as a joke, Dr. Gridlock.

I have another idea. After spending multi-billions of dollars to build a railroad out to Purcellville, we could re-dig the C & O Canal, buy some mules and ferry people from West Virginia and Ohio to Washington!

My final solution to traffic gridlock would be to take away the driving privileges of all the local politicians who allowed this overdevelopment. That would remove hundreds, if not thousands, of cars from the streets.

Bob Cochran

Reston

Dear Dr. Gridlock:

My reaction is mixed: I am a cyclist who has used the bike trail for commuting, running errands and family recreational biking; however, as a van-pooler, I am also a proponent of mass transit as a means to reduce traffic congestion, taxes, air pollution and dependence on foreign oil.

Is there a way to provide rail and retain the bike path without having to worry about road crossings?

The answer is yes, with a suspended monorail. Various renovated, turn-of-the-century train stations could actually be functional again. Pedestrian/bike-oriented micro-town centers could sprout up near stops in some of the car-dependent neighborhoods along the route.

Homes and land near such quaint traditional centers would skyrocket in value. Monorail is renowned for its quietness.

An initial segment probably would only reach as far as a terminus in Herndon/Route 28 but could be an enormous impetus for people to bike there from Ashburn/Broadlands/Leesburg for connections to more distant destinations.

When I read Mr. Regnery's proposal, my first instincts were to think of reasons why it wouldn't work. Now I believe it merits consideration in light of our region's problems with severe congestion and critical levels of pollution.

Will Stewart

Paeonian Springs

You make an intriguing case, Mr. Stewart. The monorail systems at Walt Disney World move ka-zillions of people quietly, without pollution, over several miles of track.

Surely that costs less per mile than Metrorail, or an eight-lane highway with interchanges. I agree with you this ought to be considered, if not on this route, then elsewhere.

Dear Dr. Gridlock:

The W & OD trail already is a commuter thoroughfare. I use it weekly to commute to and from work. Better than rail, my vehicle produces no noxious emissions and requires no tax dollars.

The trail can be used by HOV or individual commuters and does not require a toll or fare.

Northern Virginia is fortunate to have this lengthy cycling trail that traverses many communities and provides access to commercial/retail areas such as Tysons Corner, Vienna, Reston and Herndon.

Eliminate the W & OD trail? I propose that branch trails be added to safely funnel cyclists to the W & OD, and alternatives to vehicular traffic be encouraged.

Steven Lovejoy

Ashburn

Dear Dr. Gridlock:

Here are a few of the reasons this isn't a good idea:

* Since the railroad first began in 1847, there has been a lot of development. There are now over 70 at-grade road crossings along the trail -- pretty inefficient for a rail line.

* The W & OD trail is a transportation corridor, providing cyclists and pedestrians with a safe and direct route from home to Metro, work or shopping.

* The trail is, above all else, a heavily used recreation destination as well as an important greenway for area wildlife. As such, it enhances the lives of area residents and provides food and shelter for native and migrating birds and animals.

Julie R. Weeks

Arlington

New Metro Car Features

Dear Dr. Gridlock:

I cannot believe Metro's director, Richard White, who has asked Metro riders for their comments on survey cards handed out at Metro stations yet did not ask riders their opinion of bench seating.

He would be surprised at how many Metro riders are in favor of this. What is wrong with being like New York City? They run a clean and efficient subway system that should be a model to other subway systems around the country.

Who do we contact about our support for bench seating on Metro cars? Or, better yet, why doesn't Dr. Gridlock take a survey of how readers feel about it.

Paul Zender

Washington

The next series of Metro cars, due to go into service in 2005, will have a number of improvements for passenger comfort and safety, but bench seating is not one of them.

"Customers won't see the New York subway-style bench seating, in large part due to the fact that riders in Washington, D.C., may be on board for a longer ride than New Yorkers are accustomed to riding," said Lisa Farbstein, a Metro spokeswoman.

"A trip from Shady Grove Metro to the Pentagon, for example, takes a little less than an hour. Our customers would like to sit down if they're going to be on board for that long -- and we'd like to be able to offer them a seat."

Dr. Gridlock will be glad to see what readers think. You can also send your views to Richard White, chief executive officer, Washington Metropolitan Area Transit Authority, 600 Fifth St. NW, Washington, D.C. 20001.

Here are some of the improvements in the 2005 cars, according to Farbstein:

* Dual overhead handrails that will replace the single, ceiling-mounted, longitudinal handrail.

* The replacement of the ceiling-to-floor vertical stanchions (near the doors) in favor of seat-back-to-ceiling vertical handrails and wall-mounted vertical and horizontal handrails. This change would allow riders a clearer path when entering and exiting the cars.

* Elimination of windscreens near the doors to improve overall access.

How does all this sound?

It's Still a Car

Dear Dr. Gridlock:

I applaud the federal government for giving a tax incentive to people who purchase hybrid vehicles (Honda Civic Hybrid, Honda Insight, Toyota Prius), and I also applaud Virginia and VDOT for wanting to provide an incentive for these clean-air cars. However, I don't think granting them an exemption for HOV restrictions is appropriate.

Many of the roads and bridges in the Washington, D.C., area were not designed to handle today's traffic levels. HOV reduces the number of cars on the road and puts less stress on that inadequate infrastructure.

Granting HOV-1 status to hybrid owners gives them the incentive to give up a car pool or mass transit commute and instead drive alone.

Granted, given the number of hybrids sold today, this is negligible. However, what happens in five or 10 years when hybrid sales represent a relevant percentage of new car sales?

Hybrids are the future. However, let's introduce incentives that make sense.

Bob Clements

Woodbridge

You've given us something to think about, Mr. Clements, but I think a far greater concern about the effective use of HOV lanes is the lack of effective police enforcement.

Of every 10 vehicles you see in the HOV lanes, how many have the required number of people in them? Tell me. Based on what readers have said in the past, I'm figuring the violation rate is about 50 percent.

That tells commuters that they can use the express lanes as a single driver without fear of being pulled over.

If law enforcement doesn't get a handle on this, we risk having the HOV lanes choked with ineligible vehicles and no longer useful enough to be an incentive to share rides.

What do you folks think?

Drop Limit to Drop Speed

Dear Dr. Gridlock:

My suggestion to reduce speeding:

Drop the speed limit on all major highways by 10 mph. That way, for instance, the Beltway becomes 45 mph, and when speeders do 55 mph or more, the police will pull them over.

That way, with the 10 mph cushion built in, speeders will be going 55-60 mph (the currently posted safe speed), rather than the current, very unsafe 65-70 mph.

Robert O. Ruhling

Woodbridge

This interesting scenario presupposes one very important element: that police will ticket speeders. When is the last time you saw police ticket a speeder on the Beltway?

I'm afraid a lot of drivers are not going to slow to a reasonable speed if they can drive 70-80 mph (the current cruising speed) and get away with it.

Transportation researcher Diane Mattingly contributed to this column.

Dr. Gridlock appears Sunday in the Metro section and Thursday in Fairfax Extra. You can write to Dr. Gridlock, 1150 15th St. NW, Washington, D.C. 20071. He prefers to receive e-mail, at drgridlock@washpost.com, or faxes, at 703-352-3908. Please include your full name, town, county and day and evening phone numbers. Dr. Gridlock cannot take phone calls.