Safe separation with the Copenhagen curb?

How does a Copenhagen cycle track make bicycling safer? By putting bicyclists behind a low curb, a curb which a motor vehicle with its big tires can mount, but a bicycle can’t. The curb increases safety for bicyclists the way a streetcar track does.

Copenhagen curbed cycle track

A cyclist rides on a Copenhagen cycle track. Google Street View photo.

Oh, but wait — a streetcar track is a hazard to bicyclists, isn’t it?

So, let’s try to figure out the logic behind the Copenhagen curb. I think that it goes something like this:

“Bicyclists are sort of halfway between pedestrians and motorists, so we’ll put them behind a little curb about half as high as the sidewalk.”

This is reasoning by analogy. Reasoning by analogy is perilous if the analogy doesn’t hold. This one certainly doesn’t, so let’s look a little bit deeper.

Pedestrians (except wheelchair users) can step up over a curb, and usually encounter it at a right angle, when crossing a street from one sidewalk to another. At marked crosswalks, (in the USA anyway) we provide ramps for the wheelchair users, too.

Bicyclists usually travel along a street, parallel to a curb. A bicycle stays upright by steering to keep it underneath the bicyclist — the same way you balance a yardstick upright in the palm of your hand.

A streetcar track or a Copenhagen curb, encountered at a low angle, pushes aside the bicycle’s narrow tires. The bicyclist lands heavily on his or her hip, shoulder and/or head in what is called a diversion-type fall.

A streetcar track can divert the wheel of a bicyclist approaching from either side; the Copenhagen curb, only from the street side. A bicyclist descending into the street will feel only a mild jolt. Does this make the Copenhagen curb OK?

Only if you accept a second assumption about the Copenhagen curb — that bicyclists will stay in behind it.

Bicyclists can’t always. If bicycle traffic is heavy, the cycle track may not be able to accommodate all of it. A bicyclist may need to avoid a pedestrian who is crossing. Or, a bicyclist may be trying to enter the cycle track. Here’s an account by an American bicycle tourist, from a message posted publicly in an e-mail list archive:

I’ve jumped curbs (and objects in the road) with my other bikes many times, but did bodily damage to myself on our recent loaded tour with my NWT [Bike Friday New World Tourist, a folding bicycle]. I’m a long way from finishing up my journal, but you can read about the crash in the last three paragraphs of Day 7 at www.crazyguyonabike.com/doc/europe2007. This wasn’t a big curb, only a slightly elevated bike lane in Denmark. If you are going to attempt to jump, make darn sure you clear them. My seat post had been checked that day, but when I butted the curb, it folded, and I went flying.

Interesting, isn’t it, that a Copenhagen street design element intended to make bicycling safe — even for children, elderly adults and other especially vulnerable people — should require acrobatics to navigate!

I own a Bike Friday New World Tourist too, by the way. The seatpost would only fold due to an impact that slows or stops the bicyclist — the actual cause of the crash.

I may seem to be changing the topic now, but please bear with me.

The invisible fence that is popular with dog owners works along with a special collar that includes a radio receiver. The receiver picks up a signal from transmitters buried at the edges of the owner’s property, triggering an audible warning, and if the dog moves closer, a painful electrical shock. The product’s online promotions, all sweetness and light, studiously avoid mentioning the painful electrical shock.

Back to my topic.

The cycle track curb works similarly for bicyclists. A wise Copenhagen bicyclist knows that approaching the cycle track’s curb runs the risk of an uncomfortable and painful return.

Dogs are very territorial and will often find their way home when left off at a great distance in a place they have never been before. What a letdown, then, to get a shock on returning home!

The cycle track is like the dog fence because it carries the psychological burden of inability to return home painlessly.

The Manual of Uniform Traffic Control Devices (MUTCD) in the USA allows a bike lane to be separated from the rest of the street only by a painted marking. A motorist can, then, merge into the bike lane, just as in Copenhagen. But, unlike in Copenhagen, a bicyclist can also merge into the bike lane, without acrobatics or risk of a crash.

American streets are crowned from curb to curb. Storm drains are placed periodically at the curb, and at every low spot. Puddles and ice are only likely to form in the gutters at the edges of the street. The Copenhagen cycle track requires two rows of storm drains, yet water is still likely to pool next to the special curb, where motor vehicle tires will throw it up to splash bicyclists; and to freeze there in winter. The curb makes snowplowing and street cleaning more interesting too.

The MUTCD is under attack by some bicycling advocates who are eager to see European treatments get approval and wide use in the USA.

Some of these treatments are certainly worth considering. But as far as the Copenhagen cycle track curb is concerned, I think that the USA has the better arrangement.

When public safety is at stake, I would rather apply analysis, rather than analogies. I would also like to avoid sweetness-and-light promotion that avoids real issues. And I also would rather not be fenced in — or out — like a dog, thank you!

6 Responses to Safe separation with the Copenhagen curb?

  1. I rode in Copenhagen in 2000. Are these curbs you speak of the same height as normal U.S. street curbs? A photo or more complete description would help.

  2. My article leads with a photo! But to put it in words, the cycle track more or less splits the difference in height of a typical street curb. The cycle track is about 3 inches (5 cm) higher than the street, and the sidewalk is about the same amount higher.

    The oddity is that the curb between the cycle track and the street is objectively and obviously a hazard, yet it is promoted as a safety feature.

  3. Somehow I thought I was looking at a cyclist riding between trolley tracks!! Now that I look again I see what it is you’re really showing. Amazingly weird design.

  4. Pingback: John S. Allen's Bicycle Blog » Concord Avenue dream and nightmare

  5. Pingback: John S. Allen's Bicycle Blog » Mountable curbs

  6. Copenhagen can learn a lot about bicycle infrastructre from other places, North America isn’t one of them… The Netherlands in general, Amsterdam specifically and Malmö on the other hand are places we can learn from.

    And by the way, this is not a problem, 95% of the time, the curb is lowered, or asphalt ramps created, when bicycles are expected to cross the streets. The last 5% you just cross the curb at a straight angle – problem eliminated, its just one or two inches for god sakes.

    You do have a valid point regarding space though, it is indeed an issue, especially with nearly half the population of a million+ city where nearly half the population bike every day. But this can be solved; take a look at the map on pages 10 and 11 here:

    http://www.blivhoert.kk.dk/sites/default/files/forslag/Fra%20god%20til%20verdens%20bedste.%20K%C3%B8benhavns%20cykelstrategi%202011-2025.pdf

    It’s in Danish, but the map illustrates the most important cycle tracks where the city has decided 3 people should be able to bike next to each other (the goal is that 2 people should be able to bike slowly and have a conversation with ample space for other cyclists to overtake them), I also dig the goal that on the same network, you should be able to bike with a cup of coffee without spilling.

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