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:

I've lived in the D.C. area in four stints over a 30-year period, with time spent elsewhere allowing for a bit of compare-and-contrast observation.

I noticed the no-turn-signal phenomenon here from the start because I was one of the few using signals.

The reason was immediately obvious to me: By using turn signals, you alert other drivers that you intend to come into "their" lane. I discovered that invariably those drivers would speed up to eliminate any gap, rather than ease off to allow the merger. So drivers here quickly learn that you don't reveal your intentions or you will never be able to change lanes.

Sad, but true.

Alan Larsen

Arlington

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:

I've found that almost always someone will let me in when I'm signaling in heavy traffic.

As for your remark about your occasionally forgetting to use the turn signal, I'd argue that a well-disciplined driver would never do that. Using the turn signal should become second nature, similar to fastening your seat belt or even tying your shoes.

When I see someone next to me signaling, I will always let him in, the only exception being obvious line-cutters. If I can see someone is trying to cut in front of me but isn't signaling, I will actively box them out, within the limits of safety. Defensive-driving proponents may chide me for that, but I figure I'm just doing my small part.

I don't blame drivers' laziness for the problem. None of the local police departments has any interest in enforcing turn signal rules. Nothing irks me more than seeing a cop turn without signaling.

When I see someone turn without signaling (while yapping on the cell phone), it reminds me why my auto insurance is so high despite my clean driving record.

Greg Parker

Alexandria

Dear Dr. Gridlock:

I think the main reason people don't use them is because drivers will speed up and close the gap when they see another driver signaling. I use my turn signals, and that occurs more often than not.

Because of all the daily traffic delays, drivers in this area just don't want to allow another vehicle to get between them and their destination. If you do not signal, you have a better chance of making that lane change.

I don't condone that, but it is what I observe.

Michael Tubbs

Springfield

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:

I drive on the Beltway toward Tysons every morning, and I've seen this a million times: A driver signals to change lanes, and the driver in the other lane speeds up to prevent it.

It infuriates me every time I see it. If I see someone signal, I make it a point to give him room to merge.

Debra Cook

Burke

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:

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.

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:

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:

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

Bikes on the 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.

Of course, motorists should be more careful, and should share the road, but that will be of little consequence to a flattened bicyclist.

Bus Beats Slug Lines

Dear Dr. Gridlock:

This letter is in response to a question asked by Hal Nesbitt of Dale City on May 20. Mr. Nesbitt needs transportation between Woodbridge and Springfield and asked about slug lines so he can get to job interviews.

There is a great resource right in Mr. Nesbitt's back yard: PRTC. The Potomac and Rappahannock Transportation Commission has a bus route, the Prince William Metro Direct, that loops continuously between eastern Prince William County and the Franconia-Springfield Metro station.

Buses start running at 5:30 a.m., and trips are offered hourly (even more frequently during rush hours) until 11 p.m.

The fare is $2.50 each way. Passengers can purchase 10 tokens for $20. Free regional transfers are available for passengers transferring to other bus lines.

The Prince William Metro Direct includes stops at the Horner Road commuter lot, Potomac Mills mall and the PRTC Transit Center on Potomac Mills Road.

Customers who don't live near the Metro Direct bus route can access it by riding a local OmniLink bus.

By taking the bus, Mr. Nesbitt can start his trip home as soon as his job interview is over rather than waiting until the afternoon slug lines start forming.

For more information, call PRTC at 703-730-6664 or go to www.PRTCtransit.org.

Christine Rodrigo

Public relations specialist

Potomac and Rappahannock Transportation Commission

Thanks for the tip. That is bound to help people.

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.