In the Dec. 5 Dr. Gridlock column, Robert Gagne of Warrenton wrote:

"Anyone who drives I-66 westbound knows that the HOV lane ends at a point where four lanes become two after Manassas. Those using the HOV lane are very aware that the lane ends, and it amazes me how many will proceed all the way to the very end, then expect courteous drivers to let them merge. . . .

"I say they are the discourteous ones for not having enough forethought or courtesy to merge early and get in the appropriate lane so they can avoid this problem."

I received several responses:

Dear Dr. Gridlock:

I am a firm believer of the zipper, or alternate, rule of merging. I suggest Mr. Gagne check out Westfields Boulevard in Centreville. It is the best example I have seen of people using the zipper method to merge. Everyone knows it's coming, and about 99 percent of the time it works beautifully.

If people like Mr. Gagne decide to cut over before the lane ends, then the traffic gets bogged down because instead of allowing people to merge from one point (where the lane ends) you have to allow people to merge at numerous locations, thus having to brake constantly.

If people would open their eyes and not be so self-centered, maybe merges like the one on I-66 at Manassas would be smoother.

Michelle White

Manassas

Dear Dr. Gridlock:

Robert Gagne's letter regarding the last minute merging from HOV to regular lanes on I-66 West sounds like sour grapes. He either needs to accept that using the entire length of the HOV lane is a perk for multipassenger vehicles, or he needs to get another person to ride with him so he doesn't have to wait in the non-HOV lanes.

I see his type all the time. They're so intent on not letting people in line that they create a dangerous situation by riding the bumper of the vehicle in front of them. And we wonder how fender benders happen.

Contrary to what Mr. Gagne has justified in his mind, any arrogance, presumptuousness and discourtesy in this situation can be attributed to him by virtue of his actions and feeling the need to share it with everybody.

How hard is it to let one vehicle in? How hard is it to ensure not only your safety but the safety of others by exhibiting a little patience?

Mr. Gagne stated, "Merge when the signs start to tell you that the HOV lane will end, and avoid the problem." Well, Mr. Gagne, commuting with more than one person in your vehicle will reduce traffic, and that will help you avoid your problem.

Dean Overman

Nokesville

Rental Car Mystery

Dear Dr. Gridlock:

I am surprised by the statement by Paul Katsanis in the Dec. 5 column that most rental cars in Virginia seem to have Maryland tags. I have found the opposite to be true.

As a former area resident with family in the area, I return to the metropolitan area at least twice a year and always rent a car at BWI or Dulles. I estimate I've rented eight or so cars there in recent years, and no more than two of these have had Maryland tags.

The rest were all Virginia tags. This has always puzzled me, because most of my rentals were at BWI.

Do lots of people pick up Virginia-tagged cars at Dulles or Reagan National and drop them off at BWI? What is the true makeup of the Baltimore-Washington area rental fleet? Hopefully, someone from a rental agency can give us the full story.

Steve McDuffie

Richland, Wash.

Perhaps it is no more complicated than the ebb and flow of rental cars among our three airports. I remain open to more information.

Expecting Too Much

Dear Dr. Gridlock:

This is in response to the legion of complaints I am reading about aggressive driving and the perceived failure by the local police to enforce it.

I am flabbergasted by the lack of intelligence in some of these letters. Drivers actually seem astounded that when they witness what they believe is aggressive driving, the police will not simply write a ticket based on their observations.

Anyone ever hear of "innocent until proven guilty"? How can drivers expect the police to simply say, "Yes, you must be in violation even though we did not see it," and issue tickets based on phone calls? Amazing.

I am also tired of reading constant complaints about perceived lack of enforcement. At some point drivers need to simmer down and learn to police themselves.

There are not enough police officers to patrol the area, as some readers seem to want done. Maybe if we want to increase the Virginia sales tax by 1,000 percent to fund this, it could work, but we could not even approve increasing the tax by one-half cent, so this is not likely.

Kyle W. Thompson

Leesburg

Not Changing Her Ways

Dear Dr. Gridlock:

I recently read with interest comments made by other drivers concerning Beltway drivers and lack of law enforcement and was so happy to see I am not alone in my dismay.

I commute 10 miles on the Beltway between Andrews AFB and Alexandria every day and am amazed at the reckless, rude and uncivilized driving.

I hail from New York and have lived in Kentucky, North Carolina, Mississippi and Texas and have never seen such disregard for traffic laws.

If these drivers were in New York, trust me, they would be ticketed nonstop. Even during the worst rush hours in New York, speeding over 10 miles above the limit is hardly tolerated, to say nothing of 20 mph or greater.

I have seen law enforcement pull over a motorist on the Beltway just twice in the month I have lived here. People even speed on local roads where the speed limit is 35 mph or less, and, boy, do you get hand gestures if you drive at that speed.

The other day, I was actually gestured at several times by a very irate lady behind me because I made full stops at two stop signs.

Well, I have a message to send out to all Marylanders and Virginians: Read my lips, I refuse to speed, so if you want to kill yourselves, go for it . . . just leave me alone. And I will continue to stop at stop signs, signal before I change lanes, slow down when the light turns yellow, stop for pedestrians crossing and countless other laws that the great State of New York's Department of Motor Vehicles taught me so many years ago.

Rosanne Visco

Alexandria

Proposed Gax Tax Responses

In the Dec. 8 column, I asked readers what they thought about a nickel increase in the gasoline tax, with the extra revenue going to mass transit. Some responses:

Dear Dr. Gridlock:

I wouldn't mind paying an extra gasoline tax as long as that tax was targeted for improved public transportation (extending the Metro).

But how do we ensure that our politicians will refrain from being influenced by the builders, who really want to build more roads? As long as there is no accountability on how our politicians spend our tax money before elections, I'm not in support of anything.

Kent Gladstone

Vienna

Dear Dr. Gridlock:

We tried this by legislating that car manufacturers had to make cars with better miles per gallon. (This is known as CAFE, which means "Corporate Average Fuel Economy.") The result, according to my memory of what Washington Post auto columnist Warren Brown writes, is that the 30 most economical vehicles account for only 2 percent of auto sales, and auto companies lose money selling that 2 percent, while sales of larger vehicles -- like SUVs -- boom.

Therefore, before building more mass transit, make sure that if it is built people will use it. Don't make the CAFE mistake of assuming it.

Nevertheless, something needs to be done. For lack of a better plan, I recommend the Petroleum Independence Tax: For example (all numbers are for illustrative purposes only) a $1 a gallon tax increase, and the money raised by it would be split evenly among all people with regular (noncommercial) driver's licenses and returned to them as a rebate once a year.

To me, this would be an improvement over the way gasoline taxes work now.

Ric Rawson

McLean

Time for Resolutions As the year draws to a close, I am once again accepting your New Year's resolutions for local transportation officials and commuters.

Here are some examples:

* Resolved, that D.C., Maryland and Virginia officials will more swiftly replace burned-out streetlights and step up ticket writing for those illegally parked during rush hour.

* Resolved, that motorists will allow one merge a day in front of them. If everyone did this, there'd be a lot less stress on the roads.

I need your nominations fairly quickly. Thanks, and happy New Year!

Transportation researcher Diane Mattingly contributed to this column.

Dr. Gridlock appears Sunday the Metro section. 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.