Reader Chris Core [Dr. Gridlock, Oct. 24] asked: "Taxpayers paid for a very nice bicycle path through Rock Creek Park. And yet, whenever I drive through the park, many bikers are riding on the road, not the path, even when the path is only about two feet away! . . .

"Can anyone tell me why the bikers would rather drive dangerously near passing cars, often holding up traffic, instead of on the terrific path built for their convenience?"

I asked the audience. As usual, there is no shortage of answers.

Dear Dr. Gridlock:

I'm an avid cyclist, and even though I rarely ride in Rock Creek, I sometimes use the road in lieu of the bicycle path. Here are my reasons:

1) The "very nice bicycle path" is actually quite bumpy, and I have a road bike with skinny tires.

2) Lots of runners, rollerbladers, walkers and slow cyclists use the path, which is somewhat narrow. If I want to maintain a decent speed, without slowing down frequently, it is easier to do so on the road.

3) I only use the road in light traffic, where cars can easily pass me without slowing down.

4) Legally, bicyclists are allowed to use roadways.

If drivers strongly object to bicycles on the road, then I encourage them to contact the National Park Service and request a wider and smoother bicycle path.

Vic Anand

Arlington

Dear Dr. Gridlock:

Chris Core described the path as "terrific," and so it is (in places) for gently cruising along on a summer day. Much of it includes attractively landscaped continuous turns, with cute little hills and valleys.

On the other hand, if you're going somewhere or simply feel like riding faster, then it's not so terrific, and if we're talking about weekends, the path is heavily used by novice cyclists.

That is, on the good sections. In other places the "terrific" path is narrow, winding and seem to have been laid out by a noncyclist. Moreover, at this time of year, it's too easy to fall on wet leaves, which can be extremely slippery.

Giles Morris

Arlington

Dear Dr. Gridlock:

I commute from Arlington to Foggy Bottom by bicycle, and I count myself fortunate to live in an area with such an excellent bike path system.

It is great to see the increasing numbers of people of all ages and fitness levels commuting by bike.

One huge disincentive, particularly as the days shorten: To cross the Potomac on the Memorial Bridge (the safest and most convenient route for many or most Northern Virginia-D.C. bike commuters), one must cross the traffic twice on the George Washington Parkway, waiting for a break in the fast-moving stream before rushing across.

This is very dangerous, especially at twilight or dark. It would encourage more commuters, and more year-round commuters, if an overpass were built (similar to that at the northern end of the parkway between Rosslyn and the Theodore Roosevelt Island) for walkers and bikers.

Kathleen Stephens

Arlington

Dear Dr. Gridlock:

If Mr. Core were a pedestrian on the bicycle path -- perhaps with a dog or stroller -- he would not appreciate a 175-pound projectile zooming 12 inches past his shoulder at 20 mph. Many cyclists fit this profile and are safe among law-abiding automobiles.

Granted, though, not all cyclists are equal. Recreational bicyclists traveling at a leisurely pace and cyclists more concerned with conversation rather than speed should use the path rather than the road.

Brendan Meyer

Arlington

Dear Dr. Gridlock:

Bicycle riders ride on the road, among other reasons, because the law says they have a right to. But bike paths in and around the District are often a poor choice for anyone who wants to get from point A to B in an efficient manner. Paths are often bumpy, heaved by tree roots, narrow and twisty and generally more hazardous than the roadways themselves, at least when heavily traveled by other riders.

A strong cyclist who averages 15 to 25 mph will soon be frustrated by the paths put in front of him, which treat the bicycles as slow-moving toys rather than a sound and healthful mode of transport used by people who need to get things done.

While I don't know the Rock Creek trails well enough to pinpoint the area in question, I know from experience that many sections in the park are not suitable for any strong cyclist who -- like all commuters -- is usually trying to get to or from work as quickly as safety allows.

I commute 16 miles on paths in Northern Virginia every day and am happy to have the paths that I do. Nonetheless, I ride on the road whenever possible, given the generally superior riding conditions.

Will Rodger

Alexandria

The British Way

Dear Dr. Gridlock:

In your Oct. 24 column, reader Robert Boise of Temple Hills sought your opinion on the British traffic light pattern. He reported that their traffic lights move from red to yellow to green and then from green immediately to red. This information is not quite accurate.

The traffic signals in Britain move from green to yellow to red, just as they do here in the United States. But the cycle then moves from red to red and yellow together, and then to green. This is designed to allow drivers of manual transmissions (which is most of the vehicles there) to put their car in gear for the green light.

Traffic waiting at the red light usually begins to move as soon as they see the red and yellow together. Drivers do not run red lights as they do here -- the traffic in the opposite direction is already moving by the time you see the red light on your side!

With this cycle of lights, the strict lane discipline that keeps the passing lane clear and the marvelously efficient traffic circles, or "roundabouts," the Brits really have us beat for traffic control.

Jennifer Adcock

Alexandria

Tell me more about how driving is better in other countries, and why.

Dear Dr. Gridlock:

I am English, and I never remember lights turning from green directly to red, with no warning of the coming change. I agree with you that this conjures scary visions of rear-end collisions!

But the traffic light sequence is slightly different from here. Lights turn from red to red and yellow (meaning get ready to go), and then to green (go). They then turn from green to just yellow (meaning get ready to stop), and then to red.

Generally people do slow down on yellow, and there is not the problem with drivers running lights that we have in this area.

Georgina Bramsen

Arlington

Hurray for Clean Cars

Dear Dr. Gridlock:

I legally and economically (49-plus mpg on regular gas and a one-time $2,000 federal tax deduction for clean fuel vehicles) commute "HOV-1" in my Toyota Prius.

Please help pass the word that clean fuel vehicles (CF tags in Virginia) can legally drive in the HOV lanes with only one passenger in the vehicle.

The rude, hostile and ignorant (that means you, "BULLDOG") can refer to the Virginia Department of Transportation Web site for enlightenment. Thanks.

Lynn Simon

Gainesville

The Toyota Prius, Honda Insight and Honda Civic hybrid vehicles qualify for an alternative fuels license plate and are eligible to use Virginia HOV lanes with one person in the vehicle. They also get great gas mileage and reduce pollution. Glad to spread the word.

Transportation researcher Diane Mattingly contributed to this column.

Dr. Gridlock appears Sunday in the Metro section and Thursday in Alexandria Arlington 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. Dr. Gridlock cannot take phone calls.