Dear Dr. Gridlock:

I drive on Rock Creek Parkway most days, and on occasion I am frustrated to come across cyclists using the road instead of the adjacent bike path. Their presence is dangerous in a number of ways, such as when drivers try to pass them on the winding, two-lane portions of the parkway.

Are cyclists required to use an adjacent bike path when one is provided?

David Morgenstern

Washington

No, not in any of our jurisdictions, said Eric Gilliland, executive director of the Washington Area Bicyclist Association.

Many bicyclists eschew the Rock Creek bike path because it is cratered and cracked from tree roots and has puddles when it rains, Gilliland said. Can't blame them.

You may be interested to know that the Rock Creek bike path, from P Street NW to Broad Branch Road NW, is scheduled to be rebuilt. That project, involving the city and the National Park Service, is scheduled to start in January 2007 and take six to nine months, said the District government's bicycle coordinator, Jim Sebastian. That may take more bikes off the roadways.

D.C.'s Cell Phone Ban

Dear Dr. Gridlock:

I believe that talking on a hand-held cell phone while driving was outlawed in the District about a year ago. As a frequent pedestrian and occasional driver living near Dupont Circle, I notice more, not fewer, drivers in violation.

Have the police issued any tickets or made any arrests since the ban went into effect? It seems that when I spot a particularly dangerous driver, she or he is on a cell phone almost every time.

Bill Mould

Washington

Since the law went into effect, in July 2004, District police had issued 8,348 citations and 4,284 warnings through this August, said Kevin Morison, who handles such statistics for the police.

It seems the police are responding to the problem. Maybe word hasn't reached everyone, or maybe this is a case where the police can't get them all. Do you have any suggestions?

Towing a Truck

Dear Dr. Gridlock:

I am concerned about a very large truck carrying junk that has been parked at Fourth and C streets SW for the last couple of weeks.

It has been ticketed three times, but according to a meter attendant with whom I spoke, that is the maximum number of times it can be ticketed. The attendant also said the truck cannot be towed until a month has passed.

This is not just a meter violation, but also a violation of no-standing/parking rules during the morning rush hour (7 to 9:30 a.m.).

More importantly, this truck strikes me as a security threat, parked with unknown cargo next to federal office buildings.

Heidi Sorensen

University Park

The city says to call the catchall complaint number, 202-727-1000. Get a tracking number for your complaint, and check back in a few weeks. If the problem remains, please contact me again.

Highway Driving 101

Dear Dr. Gridlock:

I am wondering if you have recommendations for driving schools in the Washington area. I previously took lessons with a District school and got my license, but now I'd like to take lessons on highways in Maryland or Virginia. How can I wade through the listings and know which company is reputable?

Stacie Marinelli

Washington

Lots of luck. I've had one letter of recommendation for the Potomac Driving School in Montgomery County, but that's about it. Be sure to ask providers what highways, if any, the school uses. A lot of them don't go on any interstate highways.

Commercial Vehicles

Dear Dr. Gridlock:

Every morning and afternoon, as I use the Baltimore-Washington Parkway, I see dozens of commercial vehicles -- vans, trucks, cars, etc. -- also using the parkway and ignoring the "Commercial Vehicles Prohibited" signs.

I grew up near a similar parkway in Mississippi, where commercial vehicle drivers on the parkway were ticketed. Why can't the National Park Service enforce the same law up here? I always thought it was standard Park Service policy to disallow all commercial vehicles.

Is there anyone I can call? I can't take it another year!

Jonie Lehmann

Columbia

The National Park Service prohibits commercial vehicles on the Baltimore-Washington Parkway, which extends about 20 miles from the District line to Route 175.

Commercial vehicles are defined as trucks, station wagons, pickups or other vehicles transporting valuable property for a fee or providing services to another person for profit. U.S. Park Police have written 600 citations for violations in the past four years, said Bill Line, a Park Service spokesman. He said police recognize that they can't get all the violators.

By the way, the road from Route 175 on into Baltimore becomes Maryland Route 295 and is under state jurisdiction. The state imposes no restrictions on commercial vehicles on its segment.

To complain, you can call local Park Service public information officer Bill Line at 202-619-7177. Tell him Dr. Gridlock sent you.

If this is driving you crazy, I wonder if it makes more sense to commute on the parallel roads, Interstate 95 or Route 29?

Transportation researcher Diane Mattingly contributed to this column.

Dr. Gridlock appears Thursdays in the Extra and Sundays in the Metro section. You can write to Dr. Gridlock at 1150 15th St. NW, Washington, D.C. 20071. He prefers to receive e-mail, at drgridlock@washpost.com, or faxes, at 703-352-3908. Include your full name, town, county and day and evening telephone numbers.