Dear Dr. Gridlock:

I am interested in hearing your thoughts on HOV drivers who drive slower than traffic in the conventional lanes.

I know that HOV is not meant as a speedway, but it seems counter to the purpose of HOV, which is to reward drivers who carpool with faster commute times, to have drivers in the HOV lane who are driving the same speed or slower than the traffic in the non-HOV lanes.

My husband and I have been stuck behind such drivers in the HOV lanes on Interstate 66 East many times and find it very frustrating as we are going even slower than the non-HOV lanes at certain points on I-66.

Lynn Pina

Gainesville

Slower drivers should move right, even out of the HOV lanes, if a trailing vehicle is trying to overtake them. Signal that intent with flashing lights or honking.

By Virginia law, the slower vehicle must pull to the right.

If the slower vehicle will not budge, you'd be justified in passing him on the right and getting right back into the HOV lanes.

With these kind of obstacles and number of violators, I'm beginning to wonder whether the HOV lanes are a failure. Are they?

Monorail Debate

Dear Dr. Gridlock:

A monorail has a few difficulties compared with other transit systems, especially in this area.

First is safety and security. To a terrorist, I would imagine that a monorail is a preferable target. A monorail support piling would potentially seem to be much easier to take down with explosives than a solid rail bed or a (presumably highly reinforced) tunnel.

And each piling would be a target, as opposed to the intermittent bridges and overpasses that exist now (e.g. on the Red Line between Union Station and Brookland, Silver Spring Station, National Airport and the Beltway crossing south of Grosvenor), making it much harder to police and secure.

Second, monorails in some instances have difficulties with evacuation in a train malfunction. In Seattle, the monorail is being specially designed so city fire trucks' ladders can reach the car doors in an emergency. This may work well in a fully urbanized context, but for the Virginia railroad right of ways, I suspect that a full access road might be required, upping the land cost.

Third, monorail has technical issues dealing with some geographic features. For example, a crossing in the upper Potomac valley (at the American Legion Bridge or in the area of the proposed techway) would need to span a long chasm, which may be beyond the normal track construction techniques available.

Finally, monorail has problems associated with switching tracks that are not present when dealing with normal surface or subsurface metal rails (unless you are simply taking the normal metro technology and using elevated track).

Apparently, the Japanese use some sort of a technology to facilitate this in their systems, but unless something similar is employed, the ability to expand branches off the system becomes limited.

Don't get me wrong. Monorail has some distinct advantages, especially in terms of cost and disruption in the normal street grid (as we find, say, with Eisenhower Avenue and the Beltway). But we should not look at it as a panacea.

Andrew Perlmutter

Washington

Neither should we dismiss it. If it is so impractical, why are the Japanese and officials in Seattle and Las Vegas endorsing it?

Consider this: When widening an interstate highway, one of the big costs is demolishing existing overpasses and constructing new ones to accommodate the wider road. Instead of all that cost, why not build a monorail up and over the existing bridges?

I appreciate your thoughts. I'm not ready to give up yet. Please read on.

Dear Dr. Gridlock:

I think I'm missing something . . . with all the arguing over new Metro, light rail and bus rapid transit lines, why hasn't anyone mentioned elevated rail?

The Miami Metrorail has been operating since 1985; check out www.co.miami-dade.fl.us/transit/metrorail/info.htm.

It parallels gridlocked Route 1 and Interstate 95; serves historic neighborhoods, university campuses, pro sports facilities, the downtown government and business centers, urban neighborhoods, commuter suburbs, shopping malls; and it crosses the busy shipping lane of the Miami River.

All on conventional tracks, but without a single tunnel, road crossing, extra road lane, special bridge, major environmental impact or large property buyout.

It's built to withstand hurricanes, which it easily did when Andrew destroyed entire neighborhoods in 1992.

The original cost in 1985 was $1 billion, about $50 million per mile. The current projected cost for Metro to Dulles is four times higher per mile, before the inevitable huge cost overruns. Yeah, I gotta be missing something.

Alan Marsilio

Manassas

Think of Your Elders

Dear Dr. Gridlock:

I suspect that the people who want bench seats on Metro are relatively young and in good health. But reducing the number of seats in a car to increase standing capacity will only mean that senior citizens and others for whom standing is difficult (e.g., bad knee or back) will have even less chance of finding a seat.

Metro should serve all customers and not just the physically fit. Unfortunately, we all know that senior citizens cannot always rely on the kindness of strangers to get a seat on Metro.

Carolyn Fields

Arlington

State of Confusion

Dear Dr. Gridlock:

I live in Old Town Alexandria and usually use the George Washington Parkway to travel into the District.

What I've found interesting is that there is not one sign along the parkway indicating what route you are on.

Even worse, try finding the parkway when returning to Virginia over the Key Bridge! There are absolutely no signs directing you to the parkway, and, if by chance, you finally discover that Route 50 is the parkway, then try finding the turn off.

That, too, is just a throw of the dice -- almost impossible to find. There is a sign saying Route 50 East but no indication where to turn off onto it. Good luck to those out-of-towners and others trying to find their way back to this part of Virginia over the Key Bridge!

Phyllis Rubin

Alexandria

I'm afraid we've got the confluence of the two worst road signing agencies in our area: the National Park Service, which is more interested in aesthetics than providing information, and the Virginia Department of Transportation, whose spokeswoman has told me that installing improved, overhead street signs at intersections is an idea without a constituency.

You and I could do better, Ms. Rubin. Pity the out-of-towners.

There's a Cheaper Way

Dear Dr. Gridlock:

I heard on the radio yesterday that the Virginia Department of Transportation just installed some newfangled "acoustic sensor" contraption at the on-ramp to Interstate 495 from Route 236 to help prevent tractor-trailers from rolling over on the sharp curve at dangerous speeds.

The cost? Just a mere $500,000 for one intersection.

Was the metal signage company out of business? What is wrong with the simple yellow "Truck Rollover Area, Slow Down!" sign like those placed at the I-495 on ramps from Interstate 95 north? Those probably cost about $20 and certainly are not anywhere near $500,000.

This great high-tech solution we have now senses the truck's weight and speed and flashes the exact same warning message.

Virginia leaders wonder why the voters would not approve a tax hike for transportation use? I'd say this is the case in point of why taxpayers do not trust them to use the money wisely. Awful.

Kyle W. Thompson

Leesburg

Well, I voted for the sales tax increase, but I certainly take your point. Add to this the backward installation of a expensive electronic sign on Route 29 in Prince William County, plus the wild cost overruns for the Springfield interchange, and you can see why some residents don't trust the people responsible for local transportation improvements.

Transportation researcher Diane Mattingly contributed to this column.

Dr. Gridlock appears Sunday in the Metro section and Thursday in Prince William 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.