Why Bike Boxes Don’t Work (Except for Where They’re Working)

Here’s a fun little brain teaser: Where have you seen this lane configuration:

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While you pontificate that, allow me to regale you with a metaphorical vacation slideshow. Two summers ago, I was in Delft, NL as part of a PSU engineering class studying Dutch transportation infrastructure. An assignment offered a list of various pieces of bike infrastructure and asked that we ride around until we find and document an example or two of each. Most facilities were easy enough to track down. As one would expect in the Netherlands, bike facilities from the basic to the exotic were all commonplace, but one item on our checklist was conspicuously hard to locate: a bike box. Eventually, we did manage to find one lonely installation on a tiny side street downtown:

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It is worth observing and thinking about this bike box for a moment, given that it’s the only instance of that treatment in a sophisticated university city of 100,000 in the unassailable cycling capitol of the world. Why is this the only sight where the treatment was utilized, and why was it the treatment chosen for this location?

One feature that immediately jumps out is that it’s on a narrow, brick street. This means that traffic is naturally calmed–cars are limited by the physical characteristics of the street to about the same speed that bikes go (It also invites a chance to demonstrate your city’s commitment to bike infrastructure by setting the edges of the bike facility in brick!). Also, note the share of the street’s width allocated to bikes versus that allocated to cars. The wide bike lane is indicative of the fact that there are easily as many bikes that use this street as cars. And the street has fairly low traffic volumes in general; this makes it easy for both drivers and cyclists to stay aware of other traffic on the street with them. The cross street is much busier, so most of the time folks have to stop at the signal.

Look carefully at the lane configuration here. Bikes can turn in either direction, although most turn left toward the nearby train station. (Before the construction began, the bikeway to the train station was straight ahead; that configuration can be seen in Google Maps). Cars must turn right. Approaching an intersection on a bike, it’s reassuring to know that a car is turning right, whether or not it signals, and whether or not it brakes hard into the turn.

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Compare this to a bike box in Portland that has come to typify many of the problems with the treatment. The photo above shows SW Madison Street approaching SW Third Avenue. It is a primary route to the Hawthorne Bridge for both cars and bikes. It carries more cars than bikes, but enough bikes to warrant much more than the tiny sliver of road they’ve been allotted (an in which they’re legally compelled to stay). Most cars go straight, but some turn and not all that turn use signals. While traffic signal timing keeps the speeds reasonable, there’s no natural, self-enforcing traffic calming on this road. Tangentially, there is no “No Turn on Red” sign displayed, though the design guidance is unambiguous in recommending (if not outright requiring) one.

Again, take note of the lane configuration. This one should look familiar–it’s the lane configuration at the top of the post, except I drew the bike lane as a vehicular lane to fool you (did it work?). But I also wanted to make a point: you will never see this lane configuration used with two vehicular lanes due to the obvious conflicts inherent with adjacent through-right lanes. However, if you swap out the rightward vehicular lane for a bike lane, this is precisely the lane configuration that you see at countless intersections throughout Portland (and beyond).

This is the origin of the right-hook conflict. Complicating matters, the through movement gets the right of way, and in this case, through vehicles are coming from behind, often hard to see, moving at speeds that can be hard to judge, and particularly susceptible to injury in the event of a crash. That’s why the bike box here isn’t working: unless you arrive at the red phase, it doesn’t really address any of these factors. And the signals are timed such that traffic arrives mostly on green.

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Intersections like Madison and Third have given bike boxes a bad name, but they can be an effective treatment if we get choosier about where to install them. Above is a bike box on the SE Clinton Street bikeway approaching SE 39th Avenue. The similarities to the bike box in Delft are striking. It’s a low-volume, traffic-calmed street, where almost all bikes go straight and all cars must turn. Roadway space is shared until a wide-ish bike lane splits off just before the intersection. Most traffic arrives on red. The bike box does well in this scenario, organizing the queues of bikes and cars as they arrive on red, imparting a natural order to the queue clearance when green arrives. It’s a nice bit of infrastructure that’s safe and comfortable to ride on. The same conditions exist and the same treatment is used just up 39th Avenue at SE Lincoln Street, but most of Portland’s bike boxes have far more in common with the unsuccessful Madison Street installation than this successful one.

So a bike box can be a good solution if a specific set of circumstances are met. Used as a cookie-cutter solution to the right-hook conflict, however, bike boxes are the wrong thing used wrongly. So what might work better? A few experiments in the city are worth keeping an eye on. At Couch and Grand, the City is trying to tackle the visibility issue by using an unmissably obnoxious sign to tell drivers when a bike is approaching. More recently and perhaps more intriguingly, “mixing zones” are being utilized on the new bikeway on Multnomah, representing an entirely new (and in my view, more sound) approach to intersection treatments that addresses many of the issues that bike boxes don’t. (What about adding the bike box treatment to the end of a traffic-calmed mixing zone?)

In the long term, we should envision physically separate bikeways with separate green phases at our major signalized intersections. In the interim, it’s important to acknowledge that we have a uniquely Portlandian problem that will require a uniquely Portlandian solution. Our city’s grid system and small block size serves us wonderfully in many ways, but it complicates installation of safe bikeways. A bikeway is only as good as its worst intersection and we’ve got a lot of intersections in Portland. Like too many pieces of our bike infrastructure, the efficacy of our intersection treatments have not kept pace with our ballooning ridership. Portland can and should be a leader among North American cities in designing and implementing a better solution to this problem.

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