Dear Dr. Gridlock:

After reading Jim Zahrt's letter [Dr. Gridlock, May 12], I felt I had to add one comment. Yes, the HOV violators have taken over the HOV lane during the morning and evening commutes. During some evening commutes on Interstate 66, my husband and I are the only legal car out of 10.

But I see the use of the HOV lane by commercial trucks to be equal to the violator problem during the morning commute.

As development and congestion in Loudoun County continue, we have found that daily use of the HOV lane by dump trucks, moving vans, etc., can bring the HOV lane almost to a halt.

Most of these trucks are not even capable of going the speed limit. On a recent morning, a long line of traffic was stuck behind a dump truck going about 40 mph.

With the congestion in the other lanes, there is nowhere for the legitimate HOV traffic to go. HOV cars do everything they can to get around these trucks, which can be frustrating and extremely dangerous.

Can anything be done to ban this truck traffic from the HOV lane?

Diane Merna

Potomac Falls

Let's look at the definition of a truck and at trucks' use of the HOV lanes. The Virginia Department of Transportation defines a truck as weighing over 7,001 pounds. The vehicle has the word "Truck" on its license plate.

Such vehicles are banned from the I-66 HOV lanes, inside or outside the Beltway, according to Ryan Hall, a VDOT spokesman. Signs are posted along the HOV lanes prohibiting their use by trucks.

However, trucks of any size are allowed on the HOV lanes on Interstates 95 and 395, so long as they have the required minimum number of passengers, Hall said.

If you are seeing dump trucks poking along at 40 mph in the HOV lane, that could be an enforcement problem. That's nothing new. Violators are the main cause of congestion in the HOV lanes. It has been a chronic problem for so long that state highway departments must think of a new way to build HOV facilities.

The Maryland State Highway Administration, for instance, is looking at express toll lanes along the Capital Beltway and Interstates 270 and 95 that would allow everyone to use them -- for a fee deducted by an electronic transponder, much like an E-ZPass. Maryland has concluded that law enforcement cannot efficiently control the number of HOV violators, so that state is looking at different kinds of lanes.

Virginia has a ways to go. The commonwealth could start by insisting that federal funds for HOV facilities include a robust component for law enforcement.

Dividing the Dark

Dear Dr. Gridlock:

I have noticed for several years how difficult it is to see the white dividing lines at major intersections when it is raining or dark. Often headlights from other vehicles reflect off the surface of the wet roadways, masking the dividing lines to the point that a driver has to be extra vigilant to not meander into another driver's lane.

I think the solution is simple physically and worth the cost financially. Every intersection should have road reflectors installed on top of the dividing lines.

Michael S. Stanton

Alexandria

A common problem. People can't see the lines in the dark or when it's raining. There are devices that can be embedded into the pavement and reflect back light, but those are more expensive than painting the lines.

Western states use raised disks that provide plenty of visibility. Using those here wouldn't work because snowplows would scrape them off, I'm told.

Whoever solves this problem will reign forever.

A Curfew for Trucks?

Dear Dr. Gridlock:

While other readers have been busily observing cheaters in the HOV lanes, I have been observing the regular lanes instead. And what strikes me as very odd (and correctible?) is the many out-of-state 18-wheelers going through our area during peak commuter hours.

Each truck takes up the space of three or four automobiles and emits clouds of sickening fumes. And the irony is that these drivers are paid by the mile, which makes the decision to time their trips to coincide with and exacerbate commuters' suffering doubly stupid.

I wonder if a meeting of the minds between representatives of the trucking industry and traffic/highway authorities could not come up with some ideas that would benefit both the truck drivers and our local commuters.

If interstate truck traffic on interstate highways within 30 miles of the U.S. Capitol were restricted, say, to the hours between 7 p.m. and 7 a.m., I think we'd see improvements immediately, without costly road improvements.

Just a thought.

Rita Mattia

Woodbridge

As I understand it, the commercial life of our area requires access to businesses. To prohibit traffic for 12 hours a day sounds like too much of an impediment to the flow of commerce.

Transportation researcher Diane Mattingly contributed to this column.

You can write to Dr. Gridlock at 1150 15th St. NW, Washington, D.C. 20071. He prefers e-mails at drgridlock@washpost.com or faxes at 703-352-3908. Include your full name, town, county and day and evening telephone numbers. Dr. Gridlock cannot take phone calls.