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:

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:

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, 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:

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.

A Plea for HOV Lanes

Dear Dr. Gridlock:

Will Southern Maryland ever have carpool lanes? Routes 5 and 4 both are clogged with traffic through numerous lights, and the commuter buses (operating at or near capacity) must sit in traffic with single-rider cars.

As bus fares increase, more and more people get back in their cars because the only benefit of public transportation is the cost savings.

For example, I can drive to work from Waldorf to my office in the District in just under an hour. On the bus it takes an hour and a half!

I still ride the bus, but sometimes I despair of my future. I spend three hours a day commuting, round trip, and there's no relief in sight.

Recently another traffic light was added on Route 301/5 for a new housing development in Prince George's County between the county line and Brandywine. Morning traffic now backs up on Route 5 from the light at Brandywine (Route 381) to the light at Cedarville Road, almost continuously. Evening traffic backups are almost as bad.

Cathy DiToto

Waldorf

I wish I had better news for you and other Southern Maryland commuters.

The state's budget woes mean paring down new highway construction projects. Although the state would like to replace traffic lights with overpasses at major bottlenecks along the Routes 4, 5 and 210 corridors, there are no funds to do so.

Neither are there any plans to widen those roads, or to install HOV lanes.

The state has more right of way along interstate highways, and the current priority is to widen roads with express toll lanes that would be built using state or private financing and would be reimbursed through toll fees.

What's being discussed are extra toll lanes along Interstate 270, and on I-95 between the beltways, with this service in place by about 2010.

If there's any good news for some Southern Marylanders, it is that a new, 10-lane Woodrow Wilson Bridge -- plus new Maryland interchanges for I-295 and Route 210 (including the "S" curve that connects Route 210 with I-295) -- are scheduled to be completed by the end of 2008.

That will make it much easier to get to and from the District through the Route 210 corridor.

Transportation researcher Diane Mattingly contributed to this column.

Dr. Gridlock appears Sunday in the Metro section and Thursday in Prince George's 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.