Dear Dr. Gridlock:

I was glad to read Paul J. Seifert’s observation [Dr. Gridlock, March 10] about drivers who turn left and cut off drivers going straight as soon as the light turns green. The reason drivers do this is that an unending stream of straight-moving drivers makes it impossible for those poor left-turners to make their turns.

The straight-movers should stop when the light turns yellow to let the left-turners go, but instead they speed up to get through the yellow light, somehow thinking they will get to their destination sooner.

The solution is for the straight-movers to obey the meaning of the yellow light. Until they begin doing so, the left-turners will continue to have no faith and will rudely cut off the straight-movers.

In no way should we excuse these rude left-turners, but this is why they do it. It’s really a symptom of drivers’ growing frustration with traffic in the Washington area, combined with a lack of courtesy, which, when expressed behind the wheel, equates to dangerous behavior.

Heather Brown, Silver Spring

DG: Intersections are edgy places. It’s not just that we travel in heavy congestion. Drivers, cyclists and pedestrians come to the Washington region from all over the place and don’t necessary share the same expectations about one another’s behavior in traffic.

Like Brown, I think there’s no excuse for violating traffic laws or the rules of common courtesy. Turning left at an intersection is one of the most difficult maneuvers that drivers make. Try to count the number of decisions involved. How far away is the oncoming traffic and how fast is it going? What color is the light now? Is this turn I’m about to make legal? Did the traffic in the other directions actually stop for the red light? Are there any pedestrians crossing on my left? Is an impatient driver trying to pass on my left?

Mistakes can be costly, and it upsets us when another traveler’s behavior doesn’t conform to our expectations.


Dear Dr. Gridlock:

I just had one of those count-to-10 experiences when I was next in line in a dedicated left-turn lane. The person ahead of me would not budge after the light turned from a green left turn arrow to solid green.

I don’t know whether she was too timid to proceed without a clear break in the oncoming traffic or if she thought, because the light cycle includes a turn arrow, that a left turn is not permitted without it. Whichever it is, it ends up frustrating anyone stuck behind who doesn’t want to wait through another light cycle.

One engineering tweak that I saw on a recent trip to North Carolina, near Charlotte, struck me as a possible solution: At such intersections there, when the time for the left-turn green arrow has expired, it turns to a flashing yellow arrow rather than going blank, as is the case around here. Meanwhile, through traffic has a solid green light. With that combination, it’s more obvious that a left turn — though with caution, since it’s without the right of way — is still permitted.

Ralph Blessing, the District

DG: I’ve been there, too, wondering what color the driver ahead is waiting for. But it’s up to the lead driver to decide what constitutes a “clear break” for a left turn. It’s easier to be brave from the back of the line.

You won’t see many of those flashing yellow arrows for left turns in the Washington region, though they now have federal approval as traffic-control devices. The Maryland State Highway Administration, for example, wants to see more studies and review the experiences of other states, said Chuck Gischlar, an administration spokesman. The Virginia Department of Transportation is just beginning to use some.

Safety experts are interested in them as a way of reducing driver confusion, not as a technique to get drivers to turn faster. They’re concerned that when some drivers in left-turn lanes see the solid green circle replace the green arrow, they think the turn is still protected, rather than simply permitted. So they make dangerous turns into oncoming traffic.

If a flashing yellow light — rather than a solid green — followed the green arrow sequence, the driver might more readily understand the message, “You can still turn, but be careful, because the signal isn’t protecting you now.”

Adding an arrow takes time away from the straight-ahead drivers, but engineers see that there are fewer natural gaps in traffic to allow safe turns.


Dear Dr. Gridlock:

Regarding people taking left turns ahead of straight-on traffic: I am from Ohio and worked during the 1980s in southwestern Connecticut, near New York City.

I quickly learned that in New England it is an unwritten courtesy to let the first oncoming fellow at a light make a quick left in front of you before you drive straight. I assume this is an old rural custom — I can’t imagine practicing it in a large city like Boston.

Connecticut is officially part of New England, but certainly New York City is like the rest of the United States regarding left-turn yields to oncoming traffic. So, as you sat at a light you had to look in the other fellow’s eyes and decide if he was a New Englander and planned to go left when the light turned green, or he didn’t know the unwritten rule and would wait for the oncoming traffic to clear before he turned left.

I’ve often wondered how many accidents are due to regional courtesies that the other fellow didn’t know about.

Andy Marmorstein, Reston

DG: Travelers, are you aware of any such regional courtesies? The only regionalism I can think of is for transit: We stand right and walk left on Metro escalators.