Dear Dr. Gridlock:

Okay, now that you've dealt with why drivers stop well short of the stopped car in front of them at a traffic light (desire to avoid chain collisions, need to escape stalled or turning cars, or carjackers), here's a similar question:

Why do people stop one or two car lengths behind the white "stop" line when they're first in line at an intersection?

Liza Recto

Lexington Park

Probably inattention. Any readers have an idea?

Meter Hoggers

Dear Dr. Gridlock:

You recently published a letter asking how far a car must be moved after the meter has expired (answer: to an adjacent meter, or better, an adjacent block).

It is my understanding that the street meters in downtown Washington were for the customers of D.C. businesses, not for people who work in D.C.

People who park all day at the meters are making D.C. less appealing to those who need to do business there.

Christy Compton

Arlington

I agree. The city sets fixed times at meters, and when that time is up, the user is expected to move on. That can be to another meter, where the fixed time on the meter starts over again. Parking control aides often make notes of who is parking where in order to ticket drivers for overstaying the time limit.

Many of these meters allow two-hour parking. If a person is using them while at work, that means the vehicle would have to be moved to another meter at least three times a day. That's quite a hassle.

If this concept is working, curbside parking should be available for business transactions in the city. What are you folks seeing?

A Reason for Leaving a Gap

Dear Dr. Gridlock:

I am a legal transcriber, and a large number of cases I type up involve people being hit from behind at traffic lights.

What some people don't realize is that when they get hit from behind and then strike the person in front of them, they might end up being a party to a lawsuit, which means taking time off work to do depositions, and possibly going to court.

Also, in these "sandwich" type incidents, the lawyer of the last car can accuse the middle car of hitting the front car first, and that his client simply ran into the back of an unexpected wreck.

This is why I always leave room in front of me when stopped at a traffic light. And I keep an eye on my rearview mirror.

Jane Ellis

Ashburn

'Curb Aversion'

Dear Dr. Gridlock:

Your Oct. 6 column dealt with people who block a lane of traffic to drop off their video rentals, run errands or go shopping. You asked if such inconsiderate people have a malfunction in brain chemistry. My husband and I believe this is an affliction called "Curb Aversion," and feel it must be an excess of "dope-amine" in the brain.

Paula Sicurello

George Washington University

Medical Center

Department of Pathology, Electron

Microscope Lab

Washington

Keep peering into that microscope, Ms. Sicurello. We need a definitive diagnosis -- and cure -- for what makes these blockheads hold up traffic while they run errands.

Traffic No Hindrance to Sniper

The sniper did something that astonishes us road users: He vanished in our traffic.

Police were ready to pounce on the sniper minutes after the fatal shooting Monday in Fairfax County when they closed many of the roads and interstate highways in Northern Virginia. Individual vehicle checks yielded nothing.

In spite of some shootings in broad daylight, no one got a license number, and the sniper did not get caught in traffic.

I couldn't go to Baltimore in the middle of the day last week without getting stuck in traffic behind accidents on the Capital Beltway, and again on Interstate 95 in Howard County.

I found myself behind a white van with three ladders on top, and went to note the license tag, but it was obscured by one of those tinted license plate covers. I hope police will use this search to get those motorists to remove illegal covers.

I wonder if folks have any theories as to how the sniper eluded authorities in traffic, or about the police blockades.

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.