Dear Dr. Gridlock:

Continuing the discussion on cell phone use while driving, I would like to respond to Andrew Chen [Dr. Gridlock, May 6].

There are many distractions available while driving, some far greater than talking. Putting on makeup and reading are high on that list.

Talking on a cell phone, whether hands-free or not, provides a different kind of distraction from the others Chen cited and from talking with a passenger in one's car.

When eating or smoking, we are performing a basic mechanical function that we have been doing since before we were born: getting our hands to our mouths. When listening to the radio, changing a radio station or CD or even talking to a passenger in the car, we can disengage from those behaviors if the demands of driving require it.

But talking to someone who is not in the car is different. The person on the other end of the cell phone doesn't see what the driver sees and therefore can't know when it is important to stop talking to let the driver concentrate on driving. Also, the degree of distraction almost certainly varies with the importance or intensity of the conversation.

One study several years ago of driver attentiveness while talking on a cell phone used hood-mounted cameras to record driver behavior. It showed that the greatest problem was that drivers dropped their eyes from the road while they concentrated on their conversations!

The more engaging the conversation, the more the listener has to concentrate to try to pick up on the choice of words, phrasing and tone of voice -- all cues that are missing that would otherwise be provided by facial expression, body language and the like.

The more important the conversation -- an emotional one, an important business call, etc. -- the greater the concentration on the call and distraction from driving.

Camilla Stroud

Ellicott City

Thanks for one of the best-articulated letters I've seen on the distinction between cell phone use and other distractions in driving. I agree and think driving while talking on a phone is dangerous.

Ninth Street Bridge

Dear Dr. Gridlock:

Do you have any info on the Ninth Street bridge in Northeast Washington? I used to use it every weekday.

Brad Piepmeier

Bethesda

City officials tell me the bridge should be reopened by tomorrow. Some foundation erosion has caused it to be closed temporarily for repairs.

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 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.

High Gas Prices

Dear Dr. Gridlock:

I'd like to call to your attention a letter in the April 8 Washington Post by Thomas A. Firey, a senior fellow at the Maryland Public Policy Institute.

He cites two Maryland state laws that needlessly cause higher gas prices: one prohibiting refining companies from owning and operating their own gas stations and another prohibiting retailers such as Sheetz from lowering gas prices below a statewide average "wholesale price."

These laws are absolutely outrageous. And with prices for regular gas approaching $2 a gallon, the only thing likely standing in the way of their repeal is public awareness of this gross misuse of government power to enrich private interests.

Surely a Republican governor couldn't defend government price controls, right?

Jim Cohen

Bethesda

The needle on my outrage meter is moving. Anyone have anything to add?

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

Signaling in Circles

Dear Dr. Gridlock:

I spent two weeks driving around England with my family a couple of years ago, and it took a day or so, but I got used to traffic circles.

Yes, they are efficient, and I appreciate that they change the angle of "T-bone" collisions to more of a glancing blow.

But there is one difference between Maryland and the United Kingdom: turn signals. As I was quickly taught by other drivers, when entering a circle in the United Kingdom, you leave on your turn signal in the direction of the center of the circle until you approach the road you will exit onto, then turn the signal in the other direction to make your intentions known.

At the circle here I drive most often, on Perry Parkway near the Montgomery County Fairgrounds, chaos reigns. There is one road and three shopping center entrances, and you take your life into your hands trying to guess where a car is going.

Nobody signals, and everyone seems to assume he has the right of way. Of course, everyone is going too fast on top of it.

Circles have advantages, but plopping them among so many type-A drivers seems a risky experiment.

Tim Foecke

Damascus

The general rule is to look left and yield to the left when entering the circle, then move to the inside lane if your exit is more than halfway around the circle. Drivers should signal their intentions, but I fear some of them don't know what their intentions are.

Regardless, the introduction of traffic circles in Maryland has significantly reduced injuries from side-angle crashes and removed a bottleneck traffic light.

Dear Dr. Gridlock:

In your April 29 column, Thomas E. McEntee suggests that roundabouts should be installed in Virginia. He praises them as an alternative to traffic signals and notes their frequent use in England. Such is the case in many European countries.

I drive through traffic circles every day in Maryland and rarely find them safe. Only once every few days do I see anyone signal in the circle. Although circles may be efficient and effective in a system where drivers are taught proper rules and courtesy, using them at gridlocked intersections in the D.C. area is a well-intended but risky venture.

Daniel Hoult

College Park

I'm wondering if traffic circle protocol is taught in driver education classes. For driving tips, visit www.marylandroads.com.

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.