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"Bike bays" make left turns safer

As American cities become more cycling friendly, bike lanes themselves are becoming more diverse. The toolbox of street design options available to planners is broadening to include new tricks and layouts. One such new bike facility is the "bike bay," which make left turns across traffic safer.

San Francisco's new bike bay. Photo by SFMTA.

Bike bays, also sometimes called Copenhagen Lefts, combine the functions of a bike box, which provides a waiting zone for turning bikes, and a bike sneak, which directs cyclists onto a particular riding angle. The idea is to have cyclists who want to turn left exit off the main bike lane and onto a separate slip lane on their right, which then curves around 90 degrees and allows them to cross perpendicular to the original lane.

The idea should be familiar to anyone who has driven much in New Jersey, where the "New Jersey left" or "jughandle" essentially performs the same function for cars on state highways.

Sign for San Francisco's new bike bay. Photo by SFMTA.
San Francisco recently opened a bike bay at the corner of Market Street and Valencia Street, where about 1/3 of cyclists going south on Market turn left, crossing over multiple lanes of traffic. Complicating matters, Market Street has streetcar tracks, which cyclists turning left have to cross over. Without the streetcar tracks a normal bike box might do the trick, but with them the bike bay is better.

Another example of a bike bay can be found in Cambridge, Massachusetts, right outside Harvard University at the corner of Massachusetts Avenue and Church Street. There a median separates the northbound lanes from southbound, preventing cars from turning left. Rather than forcing left-turning cyclists to cross over 2 lanes of cars and rush to make a sharp turn at the curb cut, it's better to have them cross perpendicularly, with the crosswalk.

But since the crosswalk is at a major entry gate to Harvard, there's a lot of pedestrian traffic, making it desirable to separate bikes from both cars and pedestrians. Thus a bike bay, which gives cyclists their own space right next to the crosswalk.

Cambridge bike bay. Photo by the author.

So far there are no bike bays in the DC area, at least as far as I know. But it's one more potential tool to use at complicated intersections. With more bike lanes and more streetcars on the way, it's possible this may someday be a useful concept for our region.

Cross-posted at BeyondDC.

Dan Malouff is a transportation planner for Arlington and professor of geography at George Washington University, but blogs to express personal views. He has a degree in urban planning from the University of Colorado, and lives in NE DC. He runs BeyondDC and contributes to the Washington Post


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Turing left (East) From the 15th St cycletrack onto the Penn Ave cycletrack, there's essentially a bike bay there.

by @SamuelMoore on Dec 6, 2012 1:52 pm • linkreport

Seems fairly limited in its applications -- I rarely have a problem just merging into traffic and turning with the cars.

by andrew on Dec 6, 2012 2:14 pm • linkreport

This would be useful for me personally at Highland Street and Clarendon/Wilson Blvds in Arlington.

by drumz on Dec 6, 2012 2:15 pm • linkreport

Maybe it's helpful if you're turning left, but it seems to me this would also encourage the terrible and unsafe habit many cyclists have of passing on the right...

by MJ on Dec 6, 2012 2:44 pm • linkreport

This would be GREAT for turning RIGHT off the L Street Cycletrack, which I find difficult.

by Sam on Dec 6, 2012 3:06 pm • linkreport

I don't think I would use this type of facility that often in DC. I usually plan ahead and merge into the turning lane. While the bike-bay may make it easier (what is wrong with waiting at the cross walk and crossing with pedestrians), it will definitely take longer.

by sk on Dec 6, 2012 3:13 pm • linkreport

This has worked well in cities that have a lot of experience with bikes, so I defer to their experience. At the same time, I am concerned that those who turn left directly from the road way will be vilified, much as motorists complain about cyclists riding on the road and not a side path.

by SJE on Dec 6, 2012 3:23 pm • linkreport

These are most useful in places where there is some sort of obstacle to switching lanes and going across - in this case the street is two-way with a median and streetcar tracks. Not easy for bikes to get across.

There are plenty of places I could see this being useful - 15th St when you are going against traffic, or down L when you have to turn right. Penn already has a slip lane like this for bikes to wait in to turn with the crosswalk.

by MLD on Dec 6, 2012 3:36 pm • linkreport

O St. NE forms a kind of left turn lane like this for autos from Northeast bound New York Ave to Northwest bound Florida Ave.

by Lucre on Dec 6, 2012 3:43 pm • linkreport

While riders like andrew and sk might find it easier (or not an issue) to make a left from the left-hand turn lane I wonder how much more experienced you guys are at riding with traffic. This sort of facility seems tailor-made for integrating newer cyclists, people like my wife who will NOT merge into that left-hand turn lane out of inexperience and fright.

by RDHD on Dec 6, 2012 3:59 pm • linkreport

I would like to temper my original comment. While I don't see myself using it, I fully support any sort of facility that helps more timid cyclists navigate the city. And if this somehow improves upon the option of stopping at an intersection, pulling to the side, and waiting to cross with the pedestrian signal, I think it is great.

by sk on Dec 6, 2012 4:36 pm • linkreport

These jug handles would be most useful in New Jersey, where drivers also have to make left turns from the right lane.

by JimT on Dec 6, 2012 5:25 pm • linkreport

I am from NJ and had never heard a jughandle referred to as a "NJ Left". I asked my mother in law who told me that it is an old way of referring to this feature of many NJ routes. That is all.

by gooch on Dec 6, 2012 6:27 pm • linkreport

Perfect for making right turns out of the L Street Cycletrack.

by KG on Dec 6, 2012 6:55 pm • linkreport

We have a great new bike bay in Atlanta that solves a problem on a one-way street with offset cross-streets. Instead of having to make a right and quickly cross four lanes of traffic to make the left, you can just use the bike bay.
More on the project, including a picture:

by Paul on Dec 7, 2012 9:35 am • linkreport

Or you just give left turn bikers their own traffic light, just like cars do.

View Larger Map

by Jasper on Dec 7, 2012 2:02 pm • linkreport

Seems like a waste of resources.

by Ironchef on Dec 7, 2012 3:43 pm • linkreport

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