Dear Dr. Gridlock:

There's another reason you might see front license plates "missing" from cars in Maryland, as distinguished from Maryland-registered cars, which must have both front and back plates [Dr. Gridlock, Sept. 29].

The Washington-Baltimore area has a lot of active-duty military servicemen and women and their families stationed here and in neighboring Virginia. Under the Soldiers' and Sailors' Civil Relief Act, active-duty service members may keep their cars registered in their home states.

So if you don't see a front tag on a car in Maryland, glance at the rear plate before you get all excited. It may simply be a member of the military (or a visitor) from one of those rear-tag-only states!

Bill Santiff

Sunderland

Twenty-one states do not issue front tags: Alabama, Arizona, Arkansas, Connecticut, Delaware, Florida, Georgia, Idaho, Indiana, Kansas, Kentucky, Louisiana, Michigan, Mississippi, New Mexico, North Carolina, Oklahoma, Pennsylvania, South Carolina, Tennessee and West Virginia, according to the American Association of Motor Vehicle Administrators.

Dear Dr. Gridlock:

Might it not make sense for Maryland to eliminate the requirement for front license plates on vehicles? I see no benefit to having front plates in today's society. The advantages could include cost savings for the state and elimination of stolen front plates and associated problems. And your vehicle will look better, especially with today's body styles.

Would Maryland law need to be changed to eliminate front tags, or could Maryland state officials accomplish this?

James Williamson

Savage

Changing the two-plate requirement in Maryland Vehicle Law would require action by the General Assembly and governor. Bills have been introduced in the past that would require only a rear license plate, but they have failed amid opposition from law enforcement, which believes front and rear plates make for easier identification.

Law enforcement support is generally cited as the reason the majority of states still require front and rear plates, according to Jason King, spokesman for the American Association of Motor Vehicle Administrators.

Signing Up for E-ZPass

Dear Dr. Gridlock:

How, with a District-registered vehicle, can I sign up for E-ZPass to use at Interstate 95 toll gates en route to New Hampshire? I know there are a few exceptions where cash payment must be made. But automatic payment at the majority of tolls would be a big help.

Any information you can offer to point me in the right direction would be appreciated. I am leaving again on a trip in a few weeks.

Patricia J. Kelliher

Washington

Sign up with the Maryland Transportation Authority. You don't have to be a Maryland resident. Log on to www.ezpassmd.com or call 888-321-6824.

Maryland does not charge the $1-a-month administrative fee that some other states charge for E-ZPass.

E-ZPass, whose small electronic device mounted in your vehicle registers and deducts tolls from your prepaid deposit, has proved popular among motorists.

Rules for the Road

Dear Dr. Gridlock:

For years I have thought that this area needs a public service campaign to remind people how to drive.

We were all taught basic rules of the road, and some may have slipped from our focus. Perhaps some of the new drivers coming to the Washington area are not aware of the local rules. And, of course, some people just don't care that their poor driving habits are annoying and dangerous.

Maybe local transportation authorities could produce radio and TV commercials, print ads and signs that remind everyone of basic driving rules, such as slower cars keep right; left lane is for higher speeds or passing; use turn signals; don't tailgate; don't stop in intersections; and slow down in bad weather.

Those are rules that are regularly broken, but the situation might easily be improved if people received an in-your-face reminder!

Eric Wenocur

Silver Spring

Good idea.

Synchronize and Save

Dear Dr. Gridlock:

In these times of higher fuel prices, I know of a sure-fire way to reduce fuel consumption by 10 to 20 percent or more for all drivers. And drivers need not modify their vehicles or the number of miles they drive.

My savings method is traffic light synchronization. There are too few instances of traffic lights being coordinated for the load of traffic being directed.

What would it take for our local jurisdictions to implement this simple and cost-effective method to reduce fuel costs and ease ever-increasing gridlock? Isn't this the age of computers?

Tim Scott

Glenn Dale

This is a popular subject. When I ask officials about it, they uniformly say that lights are synchronized, or are about to become more coordinated.

Two of the obstructions to a free field of green lights are (a) saturation gridlock, where such timing is meaningless because of the creep-and-crawl, and (b) an equal demand on the signal from cross streets, such as at many intersections in the District, where it would not be practical to designate which street should have green light priority.

Traffic lights are usually synchronized to a certain speed. If that speed cannot be maintained because of congestion at the moment, the benefit of synchronization disappears.

One reader told me about a system in Amsterdam where overhead electronic signs tell motorists what speed to travel to make all the green lights. The Dutch may be on to something.

In Virginia, a federal grant allowed the Department of Transportation to put video cameras at major intersections along Route 7, between Tysons Corner and Leesburg, to observe and adjust lights according to traffic demands. I haven't heard that it has made much difference. That corridor is overwhelmed with vehicles.

We simply have too much traffic in the area, with more on the way.

Transportation researcher Diane Mattingly contributed to this column.

Dr. Gridlock appears Thursdays in the Extra and Sundays in the Metro section. You can write to Dr. Gridlock at 1150 15th St. NW, Washington, D.C. 20071. He prefers to receive e-mail, at drgridlock@washpost.com, or faxes, at 703-352-3908. Include your full name, town, county and day and evening telephone numbers.