I want to catch up with your responses to a May 2 column in which I asked why drivers don't use turn signals. Here are some of your thoughts:

Dear Dr. Gridlock:

Why don't people use turn signals? Because doing so is inconvenient and interferes with more important tasks, such as using cell phones, loading CDs, changing radio stations, lighting cigarettes, eating and reading.

Additionally, you have to figure out which way to move the turn signal stalk so the proper indication is given. (Yes, I've seen cars turning in one direction with their signals indicating a turn in the opposite direction.)

Car manufacturers need to offer an auto-sensing option, whereby an electrode drops from the headliner when the driver's seat is occupied. The electrode would temporarily attach to the driver's head, read his or her intentions and illuminate the proper turn signal lights.

Of course, some artificial intelligence would be needed so that the car would not respond when real intelligence is lacking and the driver intends to cut off another driver or perform a similar act.

I'm sure the auto manufacturers could resolve that minor issue.

I don't expect to see greater turn signal use until the auto-sensing option is implemented.

Barry Hollander

Columbia

I don't know about electrodes implanted in the driver's head. Seems like using turn signals would be easier.

Dear Dr. Gridlock:

It seems to me that the problem is twofold and simple.

First, there simply are laws (driving or otherwise) that go unenforced. How many times have you seen a hazardous lane change without a signal, one car length in front of a police cruiser, without any action from that police cruiser?

Second, there is a lack of solid testing in order to obtain the privilege of having a driver's license. It seems that most people are simply uneducated on the basics of driving and the laws that are established (despite their going unenforced).

Safe driving and following the rules of the road not only keep others safe, but also save on insurance costs.

Matthew Shuck

Bowie

Dear Dr. Gridlock:

Using turn signals to change lanes seems to encourage the driver in the lane you are attempting to enter to speed up. My husband says that is always true; unfortunately, I have discovered it is very often true.

Martha Knight Clements

Cheverly

Dear Dr. Gridlock:

Failure to signal, especially when changing lanes, may not be just another me-first cultural manifestation. It's a practical impossibility to simultaneously signal, steer and yak into the cell phone!

It happens so commonly in recent years. Why don't police ticket?

John Bauer

Reston

Dear Dr. Gridlock:

The turn signal has evolved into a visual Pavlovian cue inducing the driver in the next lane to stomp on the gas and close the gap.

That response has developed over decades of ever-increasing road congestion and driver frustration to produce a "you-ain't-getting-in-front-of-me-buster" mentality, which was a shock to me when I moved here from Seattle 13 years ago.

Fortunately, I've learned how to use the "blinker effect" to my advantage. With proper timing, my turn signal induces the person in the next lane to speed up while I decelerate and glide in behind that car. This little maneuver works like a charm!

Steve Alexander

Alexandria

I find that about half the time when I use my turn signals, the driver in the next lane will speed up to prevent the turn. I like your adaptation and will try it.

Dear Dr. Gridlock:

Drivers' failure to use turn signals has bothered me for a long time.

I have been driving for almost 60 years and remember the days when there were no turn signals in cars.

In those days we used hand signals to tell other drivers of our intentions. The left arm held straight out the window meant a left turn. The arm bent at the elbow and the hand up meant a right turn. The arm down and the palm facing backward meant you were slowing up.

Even though I am an old geezer, I still remember to use my turn signals each and every time I am making a turn or switching lanes.

It is beyond me to understand that if I can remember to do this, why the younger drivers don't do it. Perhaps it is just another manifestation of the lack of courtesy I see on the road all the time.

I am still an active bicyclist, and I signal my intentions when I'm on my bike. The left arm out is for a left turn and the right arm out for a right turn. When riding in a pack, I also call out "passing on the right" or "passing on the left" when I pass other cyclists.

Harvey Geller

Greenbelt

Dear Dr. Gridlock:

From countless observations over decades (not just of failure to use turn signals when turning and changing lanes but also of drivers using their turn signals after entering turning lanes), I believe many drivers fail to understand the basic philosophy of what turn signals are for. They're not to ask for permission or help; they're to inform other drivers of your plans so they can react accordingly.

Failure to properly use signals creates surprises that lead to accidents and road rage.

Some people won't use turn signals because other drivers will speed up to cut them off.

In reality, I think that if a driver uses turn signals properly (to notify other motorists of their intentions), they will discover, as I have, that having a driver speed up to cut you off is actually very rare. When turn signals become second nature you realize that, by far, most of the drivers react properly.

Once you understand that your turn signals are really there for the other guy, you start to appreciate how they help everyone. The bottom line is: Use them for all turns, all lane changes, all merges, etc.

Just use common sense and common courtesy when you drive. It benefits everyone.

Frank Detaranto

Sterling

Dear Dr. Gridlock:

Lack of proper use of turn signals has reached epidemic proportions in the D.C. area. In a five-mile drive in the Potomac/Bethesda area, I conducted an informal survey on turn signal use and observed that 75 percent of the vehicles did not signal turns.

SUV drivers were the greatest offenders, being half as likely as sedan drivers to signal.

One explanation is that SUV drivers are frequent users of cell phones while driving, which ties up one hand and makes it impossible to properly handle the turn signal control.

Lack of signaling is most prevalent when cars are in a turn-only lane. The apparent logic is that cars in the rear know that you are going to turn.

But signaling turns in turn-only lanes is very important for oncoming drivers, who may well not know that you are in a turn-only lane.

Eugene Levine

Potomac

Dear Dr. Gridlock:

Ryan Smith is mistaken [May 2]; drivers in this area do use turn signals. However, in other places they're called brake lights.

James A. Olson

Severna Park

Get Bikes Off Parkway

Dear Dr. Gridlock:

On Rock Creek Parkway this morning, southbound traffic suddenly slowed to a crawl between the Connecticut Avenue and P Street exits. The rare rush-hour backup on Rock Creek is usually attributable to a broken-down car that can't get off the road, but today's slowdown was because of a cyclist who was on the parkway rather than on the bike path.

I understand the need to share most roads with cyclists, but it seems absolutely ridiculous (not to mention rude and a little insane) for a cyclist to use Rock Creek Parkway -- a relatively high-speed, curvy road -- when a safe path is available right next to it.

I'm curious about the law here, as well as your take on this from a safety and driving ethics perspective.

Amy Levin

Washington

Bicyclists are entitled to use a lane of traffic, as are operators of motor vehicles. However, the situation you describe sounds dangerous for the bicyclist. The driver of a motor vehicle coming around a curve may not see the bicyclist in time to stop.

Double-Parkers Moved

Dear Dr. Gridlock:

The bottleneck on 18th Street NW between M Street and Connecticut Avenue, caused by double-parked cars and trucks on 18th Street, has created havoc daily for commuters. Well -- for the time being, anyway -- the police have taken notice and have been present each day this week as I have passed by that block at around 4:45 p.m.

Looks like e-mails to the mayor as well as comments to Chief Charles Ramsey during his online discussions at washingtonpost.com regarding this problem have paid off! Let's hope it lasts!

Thanks to both of them for reacting and to you for your terrific column.

Bob Henkel

Washington

Transportation researcher Diane Mattingly contributed to this column.

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