Dear Dr. Gridlock:

I want to comment on the people who think they have the right to leave shopping carts where they want just because they have children.

I have three small children, and here is what I try to do. First, I try to park next to a cart stall. Second, if I can't park next to the stall, I just load my groceries and then take the cart back with my kids in it and carry them back to the car.

It takes a few extra minutes, but it's better than leaving the kids in the car or just being rude and leaving the cart there.

Valerie Denizard

Leesburg

Someday we might have attendants push the cart to our car, unload it and take it away. That happens in California. The attendants there even carry umbrellas.

Dangers of SUVs

Dear Dr. Gridlock:

I would like very much to start a dialogue in your column regarding the book "High and Mighty: SUVs -- The World's Most Dangerous Vehicles and How They Got That Way." The author documents reasons purchasers of SUVs are considered by the automotive industry to be egotistical, paranoid, gullible saps who are at the mercy of the millions of dollars spent on marketing.

The book presents crash data showing that SUVs are more hazardous to their occupants than are large automobiles, such as the Crown Victoria.

A huge percentage of the advertising revenue of The Washington Post Co. comes from the automotive industry and automotive dealers in this region.

Companies that sell SUVs are killing people as surely as the tobacco industry, the asbestos industry and, very likely, the cell phone industry.

Dare we forget the legacy of the Pinto and the Corvair? Dare you take on this travesty?

Peter Whitehead

Alexandria

According to the book jacket, "High and Mighty" shows why SUVs:

* Are no safer for their occupants than cars.

* Have worse brakes than cars.

* Are especially poor choices for teenagers to drive.

* Have a rollover problem that goes far beyond the failures of Firestone tires on Ford Explorers.

The book is written by Keith Bradsher, formerly the New York Times bureau chief in Detroit.

My biggest complaint with SUVs is that their higher headlights strike other drivers at eye level and can cause temporary blindness. Also, from what I've seen on the rollover potential, I wouldn't want my teenager in one.

Your thoughts on SUVs?

Truck-Congested I-81

Dear Dr. Gridlock:

Just a comment on traveling on Interstate 81 as an alternative to the Interstate 95 corridor. If you don't mind sharing the road with lots of 18-wheel trucks, then drive I-81. It is a four-lane divided highway north and south from where I get on it, at Interstate 66, to where it turns into Interstate 40.

For every 10 cars there are six trucks, which is not great, especially if the weather is not good. Rain is horrible, with the big trucks splashing their spray on you.

Ed White

Annandale

You are so right. I-81 is one of the most popular truck corridors in the country.

The Virginia Department of Transportation is negotiating with a private company, Star Solutions, to make improvements to the corridor that might include new, trucks-only lanes.

The shape, cost and funding of any improvements, plus environmental studies, are matters of discussion at least until the end of this year.

Metro Emergencies

Dear Dr. Gridlock:

I, too, think it is ridiculous to evacuate an entire Metro train and hold up trains all along the line to evacuate a sick passenger [Dr. Gridlock, April 4].

You say you don't want someone dragging you off the train. I don't think anyone would advocate "dragging" anyone off the train, but I see nothing wrong if Metro personnel assisted someone off in a method determined on a case-by-case basis.

Wendell House

Silver Spring

Metro evacuates the car and, in some cases, cleans the car before putting it back in service. Medical professionals handle the treatment of the ill passenger in the car.

I would hate to be on the receiving end of treatment, and possibly injurious attention, from untrained Metro personnel.

How to Merge

Dear Dr. Gridlock:

Is it appropriate to merge into the through lane as soon as one is aware of an obstruction or impediment, or should one continue toward the obstruction and expect to be let in by fellow motorists at the point of the obstruction?

I maintain that one should get over as soon as possible. What's proper?

Kevin Moore

Silver Spring

Maj. Greg Shipley, chief spokesman for the Maryland State Police, said, "I recommend you merge as soon and as safely as you can." Shipley said motorists who zoom to the front of a closed lane and then muscle in are a pet peeve of his, but there is no law against it.

Readers have told me in the past that the Pennsylvania solution works best. That is where motorists are told to stay in the closing lane until the point of merge, and then are instructed to take turns.

I usually move over sooner rather than later because I don't want the added stress of merge mania at the front of the line.

Interstates Through Cities

Dear Dr. Gridlock:

I have been to most major cities in the country, and the one common feature is interstate highways through the middle of the cities. East to west and north to south. Washington and Baltimore are the only exceptions I am aware of.

I remember seeing the original layout of Interstate 95 and it went right through Washington, not around it. I say, put that highway back where it belongs. Also, connect Route 50 to Interstate 395 to help solve the east-to-west problem.

Gerry Ridgeway

Severna Park

I-95 was designed to go through the city, but city leaders decided they didn't want it. So the road money was transferred to the Metro system. Who is to say that was a bad trade?

Is it better to have cities compartmentalized into interstate grids, like Los Angeles, or simply cut in two, like Atlanta, where the state capital and the Martin Luther King monuments are only a few blocks away but are divided by an interstate highway?

There is little chance that I-95 will now be routed through the nation's capital.

Law on Right on Red

Dear Dr. Gridlock:

Concerning your advice to give a simple, short toot for those not turning right on red where permitted [Dr. Gridlock, May 6]: I remember reading in your column a long time ago that right turn on red is permissible and not mandatory. In other words, one does not have to turn right on red but can wait for a green light or arrow.

As a result, whenever I am behind cars that are not turning right on red, I do not honk, even briefly, figuring that the driver might be uncomfortable making the turn.

What do law enforcement authorities advise for drivers behind cars that do not turn right on red where traffic permits such a turn?

Rany Simms

Fairfax Station

It is not a question of law, because there is no law that requires a vehicle to turn right on red. One law enforcement source I talked with said he usually gives a slight toot in case the motorist is daydreaming. That's what I do, too.

Dear Dr. Gridlock:

The law that permits a right turn on red does not require it. Only the driver at the intersection is in a position to determine whether the action is safe.

Honking at the lead vehicle usually does not help, because the most natural response is to look behind, not forward.

Barbara Peters

Annandale

Transportation researcher Diane Mattingly contributed to this column.

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