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DDOT tweaks L Street bike lane plan

DDOT is still on track to build the L Street cycle track this summer. At a public meeting last week, officials presented the results of their recent study and explained the L Street plans, including a few small changes they have made based on public feedback.

Typical intersection diagram, showing new "mixing zone." Image from DDOT.

The lane uses a "mixing zone" to handle drivers turning left and cyclists traveling straight. About 140 feet before an intersection, the separator between the bike lane and the other lanes will turn into a dotted line. Drivers will merge (after signaling and carefully looking for cyclists) into the shared lane.

Some worried that the drivers would then take up the entire shared lane space and make it hard for cyclists continuing straight to get by. To address this, DDOT created a 4-foot wide bike space at the right edge of the mixing zone, which they will paint green with bike symbols. This should make clear to drivers that they should stay to the left and let cyclists pass to the right.

Also, DDOT has modified the plan to include flexible posts between the left turn lane and the other lanes. This means that drivers will have to merge back where the mixing zone starts, instead of waiting until the end.

At the meeting, several cyclists said they are still nervous about the mixing zone concept. They worried that drivers won't take enough care when merging to the left. Many cyclists like the cycle tracks because they create a feeling of greater security; WABA Executive Director Shane Farthing expressed concern that the mixing zones would eliminate that comfort factor.

However, DDOT's Mike Goodno explained that they can't replicate the layout on 15th, where the leftmost car lane is a left turn lane with a special left turn arrow. That would leave L Street with only 1 through lane outside rush hour. Also, the study of the existing lanes showed weaknesses in that arrangement on 15th. Many cyclists still go through the intersection when left-turning cars have a green arrow, and the setup on 15th makes both cyclists and turning drivers wait much longer, said Jamie Parks from Kittleson, the consultants behind the study.

A few participants asked if DDOT could continue the green paint through the intersection. Goodno noted that an an intersection, the many vehicles driving across would quickly wear away the paint. This will be DC's first foray into green paint on bike lanes.

The 15th and Pennsylvania lanes required cyclists, drivers and pedestrians all to adjust to slightly different behavior. People, even the occasional DC Councilmember, complained, but these lanes have all settled into a working pattern. With L Street and the mixing zones, there will be some more adjustment, and after some time passes, we will be able to judge whether the mixing zones work well, or not.

Other elements of the bike lane plan

At intersections that allow right turns, bike boxes will let cyclists cross from the bike lane in front of waiting cars to the right side of the road. On our post, commenter egk suggested instead placing the bike boxes on the cross streets, so that a cyclist moves left and then waits in front of the drivers on that cross street:

Image by egk.

Goodno said that he thought that was a good idea and investigated it. However, a bike box in that location blocks the curb ramps, and DDOT can't move them without far more extensive construction work.

DDOT will also be adding a more traditional bike lane on L between Pennsylvania Avenue and the start of the cycle track at 22nd Street.

Drivers will not experience much more congestion. At the most, some segments decline by 1 letter grade in "level of service," such as from B to C. The double left turn on 18th Street at rush hour will have to become just a single left turn lane.

When the lane goes in, DPW will step up enforcement on L Street to ensure that the rightmost lane stays clear for through traffic during rush hours. Drivers of cars and trucks will be able to park there off-peak, but today that lane often gets blocked even during the peak by trucks making deliveries.

David Alpert is the founder of Greater Greater Washington and its board president. He worked as a Product Manager for Google for six years and has lived in the Boston, San Francisco, and New York metro areas in addition to Washington, DC. He now lives with his wife and two children in Dupont Circle. 


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@DAl-The double left turn on 18th Street at rush hour will have to become just a single left turn lane.

If I have the location correct (18th and L?), that is actually a right turn onto L Street from 18 and, although drivers often think there are two right turn lanes, there is only 1. Police were out in force there last month for about two weeks ticketing drivers who turned right from the 2nd lane (from the right).

Am I commenting on the right intersection? Sorry if not.

by squaredeal on May 7, 2012 12:51 pm • linkreport

squaredeal: There are both types of turns. People driving north on 18th can turn right onto L, and yes, that is a single right turn. The sidewalk gets narrower to add a turn lane (not something you'd put in today).

But also, people driving eastbound on L can turn left onto 18th northbound. The leftmost lane is a left turn only lane, with parking off peak. The next lane over allows going left or straight.

The left side parking lane will turn into the cycle track and become the left turn bays for all intersections. Therefore this corner will just have 1 left turn only lane all times, instead of the current 1 left, 1 straight or left at rush, 1 straight or left other times.

by David Alpert on May 7, 2012 12:57 pm • linkreport

I still have serious concerns about drivers having to cross over the bike lane to make a left turn, paint or no paint. Why not move the bike lane to the sidewalk and have a dedicated bike light for through traffic?

by BFM on May 7, 2012 12:58 pm • linkreport

To clarify, I mean move the bike lane next to the sidewalk, not on the sidewalk itself.

by BFM on May 7, 2012 12:59 pm • linkreport

David, thank you for attending and reporting on the meeting.

by SH on May 7, 2012 1:06 pm • linkreport

I'm not exactly sure why restricting L St to one through lane during non-rush hours is being used an argument against replicating the 15th St cycletrack.

Outside of the rush hours, I frequently see tumbleweeds blowing about L St. Why the handwringing over losing a superfluous travel lane?

by JDS on May 7, 2012 1:25 pm • linkreport

Just wondering, are they still planning to build a cycle track on M Street as well? Isn't the L Street track one-way?

by Avery on May 7, 2012 1:28 pm • linkreport

Riding a bike alongside downtown traffic is terrifying. Bicycle lanes there need to be separated to be any good.

by Adam L on May 7, 2012 2:11 pm • linkreport

M Street is still something they want to do, but they aren't ready yet.

by David C on May 7, 2012 2:14 pm • linkreport

@Adam L

Fair point, but is the mixing zone really a worse option than having turning cars hook across the bike lane instead? I don't necessarily think so.

by Alex B. on May 7, 2012 2:14 pm • linkreport

Thanks DAl for the clarification. I was confused by the wording (perhaps it should read ...the double left turn onto 18th...). The right turn lane from 18th to L should be taken out and replaced with a wider sidewalk. There is little room for people to stand, let alone pass by. Lightposts, garbage cans and planter boxes squeeze people together who are trying to cross. The second lane from the right (non-turning) backs up every day with people trying to make that turn anyway so why not reclaim some of that space for peds and eliminate confusion for drivers.
Do you know if that is something DDOT considered with this intersection?

by squaredeal on May 7, 2012 2:38 pm • linkreport

Are there places where bike lanes on the left are successful?

It still seems a bureaucratic work-around that will not work in reality.

by Jasper on May 7, 2012 3:01 pm • linkreport

I'm disappointed they haven't found a way to eliminate the mixing. All the potentially good justifications notwithstanding, the whole point of a cycle track is to minimize mixing. Not doing so feels like a half-measure.

I hope there will at least be yield signs in the driving lane, indicating to drivers hoping to move over that bikes going straight have the right-of-way.

by BeyondDC on May 7, 2012 3:02 pm • linkreport

So are cyclists allowed to, you know, turn right?

by pagodat on May 7, 2012 3:09 pm • linkreport

What happens when stopped traffic in the left turning lane backs up through the mixing section?

by lemon on May 7, 2012 3:28 pm • linkreport

I'm confused as to why DC seems to have an aversion to adding curbs to physically separate the cycletracks from traffic. Why not put this along the south side of traffic, with the right side of the track along the curb? Then put a small curb on the left to separate the track from traffic, throw in bike lights at the intersections to deconflict turning car traffic and bikes, and call it done...I guess maybe because that's too easy??

by MM on May 7, 2012 4:20 pm • linkreport


Curbs are far more expensive to implement. Curbs don't just define the street and the sidewalk, they also collect storm water. Changing curbs around means you're now altering all sorts of stormwater runoff systems - and that will require much more engineering and much more cost to implement.

by Alex B. on May 7, 2012 4:24 pm • linkreport

Sometimes it feels like cyclists in DC are hapless guinea pigs for bizarro traffic engineering schemes. I hope this works out but the mixing zones seem much more terrifying to me than current conditions on L Street, which I've always found to be a relatively easy cycling route across downtown.

by jimble on May 7, 2012 5:40 pm • linkreport

This is ridiculous, drivers can barely handle L street now as it is, and it is straight, one way, and not that complicated. Add more stripes and they'll just end up doing whatever they please. Which I guess is basically what they do now anyway. So I guess it doesn't hurt to add it since it doesn't matter.

by eitor hanna on May 7, 2012 6:07 pm • linkreport

DDOT put down green paint in the bike lane in the 700 block of 15th St SE about 4 or 5 years ago.

by K on May 7, 2012 6:31 pm • linkreport

I couldn't make the meeting.

What is the holdup with DDOT building the M Street bike lane? The traffic engineering should be much simpler. In the West End M is a ludicrous 5 lanes wide and could be reduced to 3 without affecting level of service, even at rush hour.

by Matt C. on May 7, 2012 6:34 pm • linkreport

With the tweaks to the mixing zone, I'm starting to really like this plan. I think it will take some folks a while to get used to, but will eventually work just fine.

I do have some questions about the right turn bike box though. If eastbound traffic is stopped at the light, the design seems to work great. Right turning bikers will move to the bike box, wait for the light, and make their right turn. However, wheat happens if a biker reaches the bike box before the light changes. The bike box is of no help if cars are zooming through the intersection on green, so is a biker expected to wait on the left side of the street for a red, then cross via the bike box to the right side to make the turn? Wouldn't this cause a backup of bikes in the narrow lane with some still wanting to go straight? Should they be considering a turnoff "lane" or box for folks waiting to turn right? egk's suggestion makes a log of sense and I'm sure something could be worked out to avoid extensive construction.

by Garrett on May 7, 2012 6:36 pm • linkreport

@ Alex B -- I have just now invented something I call the "curb with gaps."

It's like a curb, but it has a break every few feet to let storm water through.

It costs a similar amount to construct, serves the same function, and uses less concrete.

(Seriously, stormwater can't be the reason, can it?)

by Matt C. on May 7, 2012 6:38 pm • linkreport

The mixing zone will be fine guys.

Having a separate signal, besides costing a ton more money, means more red lights for everyone.

Every second the left turn lane would have a green is an extra second the bike lane would have a red.

by JJJJ on May 7, 2012 7:10 pm • linkreport

CycleDutch explains why "mixing zones" are the worst possible solution and how the Netherlands do it better. The short summary is, cars and bikes have separate traffic signals.

by Laurence Aurbach on May 7, 2012 7:12 pm • linkreport

Great BicycleDutch video, LJ. The VéloQuébec technical guide recommends a similar approach: the bike lane to the right, with either an advance stop line or a bike box to ensure visibility. (Then, on the next page, it shows the usual U.S. treatment of sending the turning traffic across a tinted bike lane.) The section on cycletracks recommends restricting turns across cycletracks and separate signals.

Actually, there's one place where a similar treatment has been done in DC: 4th St southbound at M St SW, right outside OP's offices at Waterfront Station. The bike lane is to the right of a right-turn lane, which seems like an invitation to a right hook -- except that peds (and bikes?) get a leading pedestrian interval. Thus, the bikes are gone before the cars get the green light. (It helps that the signal for 4th is short, so you're not likely to come up to it on a green.) I was always really nervous about that intersection, but so far it's always worked fine. 9th & Penn NW, though... ugh!

Right turns will probably be done as a box turn regardless (it's how I make right turns on 15th, and it's how you're directed to turn on Penn). If you come to a red light and want to turn right, you use the bike box to cross L and go on your way. If you come to a green light, well, I guess you can pull over to the sidewalk first, or if it's clear you could merge across the empty car lanes.

by Payton on May 7, 2012 8:50 pm • linkreport

We have a mixing at almost every intersection with a bike lane, so it is really nothing new here except thatit will be marked better than along the typical bike lane. As with mopst bike lanes, requiring left-turning motor vehicles to yield before changing lanes makes sense if bike traffic is moderate. If it becomes heavy, then an alternate merge regime might be preferable, so that drivers will not be tempted to nose their way into the left turn lane.

by Jim Titus on May 7, 2012 10:50 pm • linkreport

Bigger issue with the right-most lane on L Street in rush hour is not deliveries; it is queues for vehicles entering parking garages. DPW is not going to be able to enforce that away...

by Some Ideas on May 8, 2012 11:21 am • linkreport

And out-of-town visitors thought DC was tough driving with all the circles! Encountering this complexity will drive them (and a lot of us residents) bonkers, and that's when people will get hurt.

by skeptik on May 8, 2012 11:33 am • linkreport

So the bike lane will be one-way East? Is there a plan for a one-way West lane?

by sgrace on May 8, 2012 12:40 pm • linkreport

@ Alex B:Curbs are far more expensive to implement.

So, due to cost, DDOT is going to build an dangerous bike lane. Great idea.

by Jasper on May 8, 2012 1:18 pm • linkreport

@ Jasper: The added cost would prohibit the project from moving forward. Diverting stormwater through the entire corridor would be millions of dollars in engineering, not to mention construction. I think the lanes will prove to be as safe as any other in the city once implemented.

by Dougilis on May 8, 2012 1:35 pm • linkreport

@ Dougilis:I think the lanes will prove to be as safe as any other in the city once implemented.

I am not sure. I am very unsure about the part of having a lane on the left. It seems very unusual, and most likely very confusing. I am unhappily surprised that there seem to be no examples of bike lanes on the left at all. That probably means it's a bad idea.

It's been figured out how to create good bike lanes. No need to reinvent the wheel here. Just follow the good examples form elsewhere.

by Jasper on May 8, 2012 2:20 pm • linkreport

I've been riding L Street to get home almost every day since 2001 . . . and I've got a bad feeling about these mixing zones.

If the city wants me to swap places with two-ton cars, many of which are driven by people who are far more focused on email than the roads . . . thanks, but I'll ride home on K Street or the sidewalks from now on.

by Rob R. on May 8, 2012 3:20 pm • linkreport

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