In the Sept. 29 column, reader Ruth Mundell said that since she traded an old station wagon for a Jeep Wrangler, she was having trouble being allowed to merge. It seems that more people wouldn't let her in. She asked why. Some explained themselves in the Oct. 17 column. Here is another round of driver thinking about who should get to merge in front of whom:

Dear Dr. Gridlock:

The column about drivers who won't let SUVs merge in front of them is proof of how discourteous and unsafe these drivers are. Then they had the nerve to try and justify their actions.

Why get discourteous and unsafe because a large vehicle wants to merge in front of you? These large vehicles have the right to be on the road.

Get over it, and drive safely and courteously. Stop making excuses for your poor driving habits.

Steven Billig

Leesburg

Dear Dr. Gridlock:

Say what you like about our trucks. Moan and complain all you want. Complain about 18-wheelers, box trucks and the like. Food does not magically appear on your grocers shelf; houses just don't grow out of the ground; your clothes do not suddenly appear in stores; the gas you have in your car did not magically appear.

Not everyone who drives an SUV is an egomaniac; some are doctors, firefighters, policemen, hospital workers and the like, and they have to be able to get to work no matter what.

And besides, if you did not tailgate me, you might be able to see around me.

G.W. Green

South Riding

Dear Dr. Gridlock:

I drive a Ford Expedition and a Toyota Camry, and I have found that many drivers in this area are pretty much rude to anyone trying to merge.

If people would just follow the "zipper" merging technique, as previously described in your column, and quit practicing vehicular bigotry, the traffic flow would be much improved.

This safety justification that they use for not allowing anything to merge that they can't see around is a flimsy excuse for rude and aggressive driving behavior. I'm not buying it, and neither should you or anyone else.

By using this excuse, it allows them to feel that they are morally superior to all the other aggressive drivers. If they are following at a safe distance -- not riding the person's bumper who is in front of them -- and driving a vehicle with functioning brakes, they should be able to stop safely.

Stephanie Brown

Gainesville

Dear Dr. Gridlock:

Your column made me stop and think about how I, an SUV driver, treat the drivers around me.

I am very courteous and apparently much more courteous than those who drive small cars. I allow people to merge without regard to the type of vehicle they are driving. How can someone treat people differently simply because they drive a larger vehicle? That says a lot about these folks. It is very hateful behavior and should not be taught to kids.

To limit courteous treatment to those who drive smaller vehicles is very simple-minded and rude in itself. After all, who knows who is driving that SUV. It might even be a mother with small children!

Ken Turner

Bristow

Dear Dr. Gridlock:

I read your column today about drivers being discourteous and refusing to let the woman with the Jeep Wrangler merge into traffic (among other vehicles) and the various excuses (yes, they are excuses) for that.

I call them excuses because I drive a 2002 Mitsubishi Lancer, and the same thing happens to me. The Lancer is an extremely inexpensive four-door sedan. No one has a problem seeing the road ahead with me in front of them, and I still have problems trying to merge into traffic. The real problem is that everyone on the road has the "me first" attitude.

The thing that really irritates me is when I'm trying to get over to the right, some idiot will undoubtedly try to pass me on the right and not let me over. Here's a hint: If you see a car that was going a bit faster in the left lanes slowing down and trying to change lanes to the right, it's a good bet that the person's exit is coming up and they're trying to leave the highway. Let them over!

J.D. Walker

Alexandria

Dear Dr. Gridlock:

I drive an 18-year-old Ford Ranger pickup and do allow others to merge in front of me, regardless of size; it's part of the courteous driving habits I learned 30-plus years ago during my behind-the-wheel driver's training in high school in California. Heck, I even allow line-jumpers (those drivers who use the merge lane to get in front of others) to merge!

One also wonders just how much our "winning is all that matters" culture affects our driving habits; some people may not allow others to merge just because the merging driver would then be ahead of them, thus "winning."

One thing I've noticed: not everybody signals lane changes, and some of those who do only do so after they've started to change lanes. I still follow the habit I learned 30-plus years ago: Signal for at least 100 feet before changing lanes or turning. Of course even after doing so, I've still had people honk at me when I do change lanes.

Edward Lloyd Hillman

Centreville

Dear Dr. Gridlock:

Pity the poor drivers of lower-height vehicles who "try not to let" taller vehicles merge. Poor babies!

So it's "inconvenient" for some people to drive behind me, so they "try not to let" my big, scary van merge. These, no doubt, are the same people who gladly merge when I slow a little to let them in, and who rush around me and pull in front when I allow a safe distance between me and the vehicle I'm following.

Wayne Keyser

Arlington

Transportation researcher Diane Mattingly contributed to this column.

Dr. Gridlock appears Sunday in the Metro section and Thursday in Loudoun 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. Dr. Gridlock cannot take phone calls.