Why Does Bicycling Explode on Streets With Two-Way Bike Lanes? And Should This Type of Bike Lane Be Avoided?

Lloyd wrote up a great article yesterday summarizing the epic bike protected bike lane study that just came out from the National Institute for Transportation and Communities. I'm going to dig in a bit more on one point – the explosive growth in bicycling on streets with two-way protected bike lanes. And I'll also examine some criticism of these bike lanes.

First of all, just to be clear what we're talking about, above is a cross section of a street in Austin, Texas, with protected two-way bike lanes. Here are some before and after pics of this street as well:

© NITCWhile bicycling increased quite a lot on all streets studied where protected bike lanes were added, but it really exploded on two of the streets where two-way bike lanes were added. In the case above, there was even a conventional bike lane in place before this two-way one was created, making the growth that much more impressive.

© NITC

Before discussing why this type of bike facility might have increased bicycle rates so much, below is a cross section and some pictures of Dearborn St in Chicago, where biking increased a tremendous 171%. I'm not sure why the cross section doesn't include flexposts – you can see them in all three of the "now" pictures above.

© NITC

© NITC

So, why does this particular type of bike lane seem to increase ridership so much? And are there issues with such bike lanes? (Hint: yes.)

I doubt the dramatic ridership growth because bicyclists are afraid they will need to make a U-turn somewhere along their route. I think the big draws of such bike lanes are that they are much more visible, which makes people notice them and consider biking for transportation, and that they seem to be much safer at a glance, which has the same effect. Furthermore, in both instances above, there were flexposts present, which further increase safety, sense of safety, and visibility.

It's worth noting that there are some downsides to this type of infrastructure, however. Well, there's essentially one big downside. People in most countries of the world are in the habit of looking for oncoming traffic on their left when they are turning left, but two-way bike lanes result in bicyclists coming up from the far left on the back side. Copenhagenize's Mikael Colville-Andersen discussed this yesterday in an article that seems to be in response to the NITC findings but doesn't specifically mention the report. Here are some of his thoughts:

In Denmark, the on-street, bi-directional facility was removed from Best Practice for bicycle infrastructure over two decades ago. That in itself might be an alarm bell to anyone paying attention. These two way cycle tracks were found to be more dangerous than one-way cycle tracks on each side of the roadway. There is a certain paradigm in cities... I'm not saying it's GOOD, but it's there. Traffic users all know which way to look when moving about the city. Having bicycles coming from two directions at once was an inferior design.
This was in an established bicycle culture, too. The thought of putting such cycle tracks into cities that are only now putting the bicycles back - cities populated by citizens who aren't use to bicycle traffic - makes my toes curl.

He also references a December 2013 OECD report that advises against two-way bike lanes on the street. (Going through parks, the safety issues disappear of course.)

And he quotes Theo Zeegers of the Dutch national cycling organisation, Fietsersbond, in order to share his opinion on the matter: "Bi-directional cycle tracks have a much higher risk to the cyclists than two, one-directional ones. The difference on crossings is about a factor 2. So, especially in areas with lots of crossings (ie. builtup areas), one-directional lanes are preferred. Not all municipalities get this message, however."

So, you've got two conflicting points here: one is that two-way bike lanes are correlated with stronger bicycling growth than any other type of protected bike lane in this NITC report (more research needs to be done to confirm causation, not simply correlation), and second is that on-street two-way bike lanes are considerably less safe than on-street one-way bike lanes according to numerous bicycle planning experts and authorities.

The questions I'm left with are: Is it more worthwhile to attract people to bicycling than to build the absolute safest bike lanes? (Remember that bicycling also increases a great deal as ridership increases.) Is there any possibility two-way bike lanes could perform better in the US than in Europe? (I don't see why that would be the case.)

Mikael has a very clear opinion on this matter: "If someone advocates infrastructure like this and actually believes it is good, they probably shouldn't be advocating bicycle infrastructure."

Your thoughts?