Dear Dr. Gridlock:

I keep reading and hearing about this 12 mph window over the limit as the enforced speed limit. Who decided this? Is it true for all roads, streets and highways in all municipalities in the Washington area? What about in work zones where the posted speed limit has been reduced from 65 to 55?

Ken Beal, Urbana

DG: When in doubt, a driver could always choose to obey the speed limit. That would pretty much eliminate the chances of getting a speeding ticket in any jurisdiction under any circumstances.

Maryland happens to have a law limiting the use of speed-enforcement cameras that says drivers must be going at least 12 mph over the posted speed limit for a ticket to be issued. Enforcement cameras are particularly controversial among drivers, who also happen to be voters. The Maryland General Assembly was willing to approve camera enforcement but only with the 12 mph buffer for allowable misbehavior.

The District, which also uses speed cameras, has no such buffer in its law.

Police officers everywhere — including the ones whose presence is such a downer for drivers on Maryland’s new Intercounty Connector — don’t face a 12 mph limit on their powers, and their tickets are a lot more expensive to pay than Maryland’s $40 speed-camera citations.

Drivers in Maryland might encounter the speed cameras in highway work zones. There’s a zone on the Capital Beltway in Silver Spring where the State Highway Administration is rehabilitating the bridge over the Northwest Branch.

The state sometimes lowers the speed limit in a work zone for safety reasons. That wasn’t the case in the Beltway work zone. There, the speed limit remains 55 mph. In any of the work zones with camera enforcement, drivers see several warning signs posting the speed limit and reading, “SPEED PHOTO ENFORCED.”

Despite signs, the consistent work-zone speed limit and the Beltway congestion that makes accelerating to the speed limit a challenge during many hours, state records show that 30,986 drivers managed to generate tickets from cameras between August and December.

On the upside, the camera tickets seem to have an effect: In August, 12,001 citations were issued. No other month had half that total.


Dear Dr. Gridlock:

Of the three escalators at the Ballston-MU Metro Station leading riders to trains heading to the District during the morning rush hour, two are always ascending. The only one going down is farthest from the entrances with the Metro Farecard vending machines. This makes no sense in terms of either volume of passengers or Metro’s stated goal of spreading riders along the entire length of the cars. At a minimum, Metro should just stop the first escalator, allowing it to be used as stairs in either direction.

Ralph Ives, Alexandria

DG: I hear similar complaints about escalators from many riders at stations with various configurations. The up-down pattern doesn’t strike them as logical.

Metro spokesman Dan Stessel told me recently that many of the transit system’s escalators are in a two-up, one-down configuration regardless of the time of day. There are several reasons, he said.

In an emergency, it’s better to have two ascending escalators. Also, people descend faster than they ascend, so riders usually aren’t delayed as long as there is one working escalator going down. More generally, he said, think about the flow of traffic in and out of a station. There’s usually a rather even flow of people walking in. Contrast that with the surge that occurs when two trains arrive on a platform at the same time. That makes two “up” escalators particularly useful for clearing the crowd.

Stessel also confirms an explanation that riders sometimes hear when they ask station managers about the direction of the escalators: Constantly switching an escalator’s direction can cause it to break down faster.

About the alternative of stopping an escalator and using it as a stairway: I hate that, and many riders tell me they do, too. A stopped escalator can be difficult to walk up and down. The spacing between the steps is uneven, and the steps might not be well lit. Also, some people won’t stay to the right as they walk, so they block the entire passage.


We have a continuing dialogue about bad behavior by drivers, including those who don’t use turn signals. This traveler doesn’t see it as a widespread problem.

Dear Dr. Gridlock:

Either I live a charmed life, or the situation with use of signal lights isn’t quite as bad as reported in recent columns. I have had occasion to drive all over some busy parts of Montgomery County — Bethesda, Chevy Chase, Silver Spring, Rockville — and into Prince George’s County. I’ve also gone to the Kennedy Center just before and during rush hour.

The vast majority of drivers I observe use their lights and do so well before their actual turns. In left- and right-turn lanes, fewer do. But, after all, their location is an indication of their intentions, and even when there, many do signal.

Of course, there are those who do not signal, and that is regrettable, but let’s not turn exceptions into a pattern. By the way, I lived in New York for 20 years and have been back often. Those good folks are no better or worse than my neighbors here.

If you want to deal with a serious problem, go after drivers who do not turn on their headlights in the rain, turning their cars into phantoms on dark days.

Daniel Mann, Bethesda