Success! 12th street northbound @ Mass Ave NW Lane change implemented

12th and Massachusetts Avenue, NW

“Dear PoPville,

Dropping you a follow up from one of your posts a while back [Nov. 2013]. Traffic arrows appear to have been changed since monday 12/1 at the latest? Now two left lanes go left, second to rightmost lane goes straight, and rightmost lane goes straight or right.”

25 Comment

  • Yay! Thank you DDOT for making a sensible improvement!

    • Did they add an extra lane to 12th on the other side of Mass? Because if not, there will still be a cluster of cars blocking the intersection as they funnel into one lane.

      • I don’t know the answer to that, but as I said below, in my excitement over a lane to go straight that doesn’t offer a left turn I totally (and stupidly) overlooked the optional straight arrow on the right lane. Oops.

  • Finally! It actually reflects how people use it!

    It’s still 2 lanes into 1 lane at an intersection, which is a big No in traffic engineering. And a similar issue on 12th at Penn where 3 approaching lanes turn into either 2 or 4 lanes, depending on whether cars are parked. Aaaand that huge unmarked lane shift across Constitution that sends cars vying at each other into the center and right lanes…

    • Agreed. That intersection is always a source of frustration when headed north on 12th and I am glad DDOT noticed it was a problem. However, there is only one lane headed north after the intersection, so you still have the merge problem that will back up that intersection. It is not clear which lane has to yield and which one has the right of way. It will remain a cluster.

      • I’d much rather they replace the rightmost lane with a bike lane (connecting the L St lane w/ the 12th St lane) and then fill in the rest with widened sidewalk alongside Burke Park. That fourth lane simply provides offers no use.

        • Exactly. No one should be turning right onto Mass there, as there’s an opportunity to turn right on L before that leads right to Mass.

        • Yeah, I think the right lane seems mostly unnecessary. If you are headed north on 12th and want to make a right on Mass, it is better served for you to take the earlier right on L St, which merges on Mass in 1 block. Also, that right lane on 12th prior to that small block next to the park is a parking lane, so it is an expansion to the flow of traffic for a very limited purpose. Repurposing that right lane is a good idea, but I would worry about cyclists getting cut off by cars trying to go straight on 12th and moving around a backup of cars turning left on Mass. Not sure what the best answer is.

    • I was so excited that you can only go straight from a lane that I totally missed that. That’s bizarre and is going to confuse people.

  • tonyr

    Now if they could find some way to prevent the eastbound Mass. Ave. traffic from blocking the box we’d be all set.

    • +1, but I don’t think this new flow solves the problem, because now there’s 2 lanes merging to 1 in the middle of a busy intersection!

      • Practically, it’s always been that way, as people in the right lane would continue straight and merge with those in the center lane.

  • I live right near here and it drove me crazy when people in the right lane went straight. I get this is just what people do but it makes zero sense to have two lanes go straight into one lane. This intersection is often jammed and part of it is nonsense like this.

  • The lane allocations make total sense. But I think the light timing is off or something. There has been a much longer line of traffic to turn left since the change occurred.

    • No one needs to worry about the two lanes merging into one. We’ve studied the issue extensively and have found and implemented a solution. Because Massachusetts Avenue traffic is always blocking 3/4 of the intersection; in practice-only one lane from 12th Street will be able to get through at a time. PROBLEM SOLVED.

    • There is now a left turn signal which is green only for a fraction of the time the green to continue through is on. Probably bunking things up a bit.

  • While I am glad there have been improvements this was not the design that went through the ANC. There were to be a couple of parking spots north of Mass that were to be eliminated to allow for the merge to take place north of Mass.

  • I moved to this area on Labor Day of this year, and the intersection has been configured like this since at least then. It is not a fun intersection to be a pedestrian, especially when trying to cross Mass Ave while on the west side of 12th St and you have to race the two lanes of left turning drivers to get across the street before they cut off the sidewalk.

    • The point of this post is that the intersection was just re-configured last week. There is now a left turn arrow so you won’t have difficulty crossing.

  • Doesn’t help that unfamiliar drivers don’t see the arrows until they are near the intersection

  • I’m not sure that it will make much difference. Most people (like me the first time I drove through this intersection), look at the arrows on the street, and by the time you see which lane you are in, you’re too close to the intersection and too stuck in traffic to change lanes. Thus people change lanes in the intersection anyway. It will continue to happen, and even with the cops directing traffic at rush hours, it didn’t solve the lane change issue (though they mmmoooostttly kep the intersection clear).

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