16.5.12

Bicycle Curb Cuts & the Devil in the Details

[An at-grade curb cut on the Phalen Boulevard bike path in St Paul.]
Talk is cheap. Concrete is expensive. If cities really want to encourage bicycling, and seduce  people into riding bicycles or walking around to get places, it’s not the thought that counts. It’s not enough to simply mark a street with some bicycle symbols, or stripe a path, or put up a sign, or start an education campaign over youtube. The devil is in the details, how precisely bike rou8tes and paths are built and maintained over time.

This is particularly true at intersections or places where there's a transition between one type of path and another. Cities can spend lots of money and energy on a nice bicycle route, but if it's punctured by a terrible encounter with a wide busy road (e.g. Hiawatha Avenue without the Sabo Bridge), the appeal of bicycling evaporates.

For example take curb cuts. Every time a driveway or a parking lot or a street intersects with a bike path, there’s a choice to be made. Do you prioritize the automobile traffic and force bicycle riders to go awkwardly up and down the often-crumbling curbs? Or, do you prioritize bicycles and pedestrians and force cars to go up and down a ramp.

This is the question before engineers each time they design a bike path, particularly an off-street one. And in the USA, 99.95994% of the time the answer is to prioritize cars.

Well, that seems like the wrong choice to me for a few reasons. First, these bike path intersections can serve as speed bumps, slowing down car traffic at precisely the intersections where they most need to be cautious. Second, the grade separation signals a point of difference for car drivers. The elevation change physically marks a difference between the parking lot or street, an encounter with pedestrians or cyclists who may be zipping past.

Third, and more subtly, having an at-grade curb cut really makes a difference for people riding bicycles or in wheel chairs. Each time you have to slow down and cautiously bump your way up and down another curb cut, it destroys a little bit of your joy. It’s the bicycling equivalent of dog owners picking up poop. Imagine the increase in canine misery if humiliating ordeal happened every 125 yards!

In my bike trips experiences in Europe, I’ve seen off-street bike paths that prioritize cyclists, forming  a nice level path for people doing active transportation. This is pretty rare around here, though. Almost the only example I can think of is the new Phalen Boulevard bike path, where the cur cuts are designed to keep bikes on the level. I say it all too rarely, but good job St Paul!

[A great curb cut on the Phalen Boulevard bike path in St Paul.]

2 comments:

Reuben Collins said...

Great post! Great photos! Do you mind if I use the photos professionally (i.e. include them in reports created by my for-profit employer)?

Sometimes we forget that the primary reason curbs exist is to convey stormwater. Where a need to convey stormwater is not critical, neither are curbs. This should be a standard design feature at private driveways, and should at least be considered at low-volume public intersections.

Reuben Collins said...
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