We return now to the topic of fog lights, driving lights and auxiliary lights of all sorts. I don't like them. They add to the general illumination explosion caused by oncoming vehicles, especially those high off the ground, such as SUVs and pickups. Two oncoming headlights are bad enough, but four? Or six?

When we last visited the subject Jan. 22, readers gave their reasons for using auxiliary lights. The lights help illuminate potholes and critters on the side of the road, they said. But, as readers point out today, even with the improved fog light illumination, you'll be upon that pothole or critter too fast to avoid it.

Helps other drivers see me, they said. But I can see your oncoming headlights plenty fine (sometimes too well) without your being lighted up like a Christmas tree.

Short of rural or foggy driving, it's hard to make a case for using those extra headlights in our typical urban and suburban driving.

Here are more of your thoughts:

Dear Dr. Gridlock:

Where can I have my headlights adjusted ? Every shop I have called says, "We just aim them against a wall." Do you know of any shops that still have the machine for correctly adjusting headlights?

William Oliver

Dunkirk

Yes, but they are in Virginia, which requires an annual safety inspection. Maryland does not.

Perhaps readers in your area will have a suggested spot closer to Calvert County. If not, any Virginia inspection station (they frequently are at gas stations) should have equipment to properly aim headlights.

Dear Dr. Gridlock:

Unfortunately, not all auxiliary lights are adjusted correctly. Those that are not create a real hazard for other drivers, often in already dangerous conditions: rain, night, unlighted roads.

Auxiliary lights are like high beams in their ability to blind other drivers. In the case of high beams, drivers usually lower their beams when they meet another car, no doubt because all cars have high beams and because of the "reminders," not to mention retaliation, that can quickly ensue.

Those who think they cannot drive safely without the added help of auxiliary lights (an issue in itself) could help everyone by treating those lights as high beams -- using them only when really needed, dousing them for oncoming cars and when stopped at intersections, and regularly checking to ensure that they are appropriately directed.

Fran Guillermo

Silver Spring

Dear Dr. Gridlock:

I detect some foggy reasoning for the use of fog lights in some of your readers' responses. Steven McArthur said fog lights that illuminate "the shoulders and ditches" help him to see deer sooner. I haven't seen any deer that low that were still alive.

And Dave Shuffelton said his lights shine about eight feet in front of his vehicle. At 30 mph, you cover about 40 feet in one second. Do the math: 0.2 seconds is fast even if you are paying very close attention!

I am not saying the lights don't have a place. I occasionally use low-watt fog lamps in rural areas and on the rare occasion that regular headlights in fog reflect too much to see. I also use them as daytime running lights in early morning and dusk to enhance my visibility to others.

I see little need for the use of them, or the newest high-energy headlamps, in most urban areas. I find both of those so bright that they affect my ability to see the road.

John Rausch

Rockville

My sentiments exactly.

Dear Dr. Gridlock:

I am continually amazed at all the self-serving blather everyone continues to promulgate with regard to their inappropriate use of fog lights. The technical term "fog light" should be sufficient: One should use fog lights only in the fog! If you can't see at night with headlights, you probably shouldn't be driving!

I suspect the only way to stop or mitigate the fog light problem will be to pass a law prohibiting them, much as for driving with cell phones.

John Binford

Silver Spring

Dear Dr. Gridlock:

What's all this whining about improperly lighted streets in suburban subdivisions being so dark that people can't safely drive unless they use their fog lights?

Guess what, folks? Outside of cities, in places such as central Pennsylvania, where I grew up, we didn't have lights on roads outside of town. We had a light on a pole that came on at dark by most houses, but that didn't mean it was near the road.

I understand that with technological advances comes safety, and fog lights have their place. But don't use the excuse that the lack of lights on suburban or country roads makes you an unsafe driver.

If you slowed down, paid attention to the road in front of you and stopped talking on your cell phone, you'd find that properly aimed headlights on clear nights should do fine.

JoAnna Wilson

Montgomery Village

Dear Dr. Gridlock:

You asked readers if their auxiliary lights can be turned off. Yes, I can turn them off.

I use my fog lights as supplementary driving lights to better illuminate the road. I am not satisfied with the light pattern of the (correctly adjusted) headlights on my car, and the light from the lower-set fog lights helps even out the patchy areas. They even project some light to the sides to help me better see and avoid what could soon be in my path, helping make me a safer driver.

The fog lights would be blinding only if they are misadjusted. Mine are adjusted low, as is appropriate for foggy conditions, and I have not had any drivers flashing their lights at me, as would occur if I had my high beams on.

Ken Kuhn

Germantown

Dear Dr. Gridlock:

You got slammed with a lot of justification for why people use fog/driving/auxiliary lights. One reader from Germantown said he used fog lights to spot deer. Well, a true fog light (properly aimed) is not likely to help in that instance; that is what driving lights were designed for.

Another reader responded that his lights are used to avoid potholes and that they strike the road eight feet in front of the vehicle. At 25 mph, eight feet is covered in 0.127 seconds -- not really enough reaction time. Maybe he is driving at 8 mph.

Another response was from a driver who stated she needed the extra light to help her see safely at night. But what about the people who are affected by the extra glare? Are they to stay off the road when she is driving?

Now let's look at the real picture. A true fog light has a reflector and lens system that creates a wide, flat beam -- flat to reduce bounce back and wide to illuminate the edges of the road. These should be used alone or with low beams.

A driving light is designed to provide even more light than high beams, for rural driving. In most states, the use of a driving light falls under the same constraints as high beams when meeting oncoming traffic or following another vehicle.

I often rent cars, and in the cases where the car was outfitted with these additional lights, there was a switch for turning them off. Also, I have seen little difference in having them on vs. not having them on; therefore, I make sure they are off.

Finally, one reader suggested that without a state inspection the lights are not properly adjusted. I doubt that these factory-installed lights have any means of adjustment.

I lived in Pennsylvania, and few, if any, inspection stations ever checked head/fog/driving light aim unless they had good reason to believe the lights were out of alignment.

In Maryland, police have a form for safety equipment violations that covers lights, the exhaust system, windows and everything imaginable, but I wonder how many of them are ever issued.

Paul Holzer

Mitchellville

Thank you for those observations. I agree.

Dear Dr. Gridlock:

I am confused by this ongoing discussion about using headlights in bad weather and turning the lights on when windshield wipers are in use. Don't most cars made in the last five years or so have daytime running lights?

I have a 1999 Toyota Corolla, and the lights go on when the engine starts. You can't turn them off if you want to. I first noted the feature on a rental car, before I had the Toyota, and thought there was some malfunction. I've come to rely on it, and I'm never worried about needing to turn on lights.

Harise Poland

Greenbelt

You are talking about the headlights, and not auxiliary lights, that come on automatically when the windshield wipers are in use or the vehicle is started. A nice feature.

Dear Dr. Gridlock:

Some cars have headlights that are automatically turned on when the wipers are on. My 2001 Buick LeSabre does that.

Clifford Comeau

Beltsville

Dear Dr. Gridlock:

I have a 2003 Cadillac DeVille, and when the wipers are engaged, the headlights automatically come on. I'm sure a lot of vehicles have that feature.

Jan Danley

New Market, Va.

That sounds like a wonderful feature, one that will also help bring forgetful drivers into compliance with the law. "Wipers on, headlights on."

Bag Shopping

Dear Dr. Gridlock:

A couple of years ago, I, too, was in the market for a car seat bag that I could carry over my shoulder through the airport to the gate, as car seats are rather bulky to carry.

My local Babies "R" Us at that time sold a car seat bag for approximately $20.

Now that we have moved from forward-facing car seats to high-back booster seats, we check the bags.

Jim Kempton

Seabrook

Dear Dr. Gridlock:

There is a market for those car seat travel bags, and they can be purchased from virtually any baby products Web site. We just bought one for our Bahamas Christmas vacation.

Buyers must be aware of the size because there are several. If the Web site has a section for buyer comments, they should read those. And they should certainly shop around. The carriers cost $12 to $75.

Tim Archer

Bowie

Driving in Parking Lots

Dear Dr. Gridlock:

I read somewhere recently that there is no public right of way in parking lots because they are privately owned. If that is true, drivers who get angry at other drivers backing out of spaces are in the wrong.

First, they should not be going fast enough for a car backing out (very slowly) to cause a dangerous situation; more important, they have just as much responsibility to yield to a car backing out as vice versa.

I, too, frequently encounter that problem, and my answer is just to go extremely slowly and hope for the best. I haven't encountered very many angry drivers, though. And I would never honk my horn to alert drivers that I am backing out, as one writer suggested. They probably wouldn't realize it was coming from a car backing out, plus it would annoy and scare pedestrians nearby.

I wish all drivers would refrain completely from honking horns in parking lots except for in the most urgent situations.

Tracy B. Lynge

Columbia

My advice is to look for two empty head-to-head spaces and drive through one and into the next, leaving your vehicle facing forward. You might have to park a little farther away, but getting out of the parking spot will be less stressful.

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.