What is the Hierarchy of Controls, and what does it have to do with bikes?

Queen Anne Greenways hierachy
© Queen Anne Greenways

It tells us that we are doing the wrong things first because they are easy.

When I was an architect and then a developer, messy construction sites made me crazy. There could be trip hazards and fire hazards and fall hazards, but all the supervisors cared about was whether you had steel toed boots and a helmet. That's why the National Institute for Occupational Safety and Health (NIOSH) developed its Hierarchy of Controls, to demonstrate that the hats and boots are the last things to worry about, after removing or replacing the hazards or separating the worker from it. But it is cheaper and easier to yell about the hats.

hierarchyNIOSH/Public Domain
It is a problem that keeps coming up; as the Center for Disease Control notes, the important stuff at the top is hard.

Administrative controls and PPE [personal protective equipment] are frequently used with existing processes where hazards are not particularly well controlled. Administrative controls and PPE programs may be relatively inexpensive to establish but, over the long term, can be very costly to sustain. These methods for protecting workers have also proven to be less effective than other measures, requiring significant effort by the affected workers.

Actually fixing the problem is "the most difficult to implement in an existing process. If the process is still at the design or development stage, elimination and substitution of hazards may be inexpensive and simple to implement." So they go after the easy stuff that you can just check off. They yell about the hats.

Roads are dangerous places and a lot like construction sites, where people, equipment, and hazards are all in the same space. This is why a lot of activists and advocates for people who walk and bike keep bringing up the Hierarchy of Controls, to try and move the emphasis from bike helmets or wearing high-visibility clothing to actually fixing the problems. We showed one a few years ago from Don Kostelec, which is particularly focused on bikes.

Hierarchy of street controls© Hierarchy of street controls/ Cathy Tuttle

Cathy Tuttle, a candidate for Seattle City Council, produced a different version, less graphic than Don's but with a good explanation of what can be done at each level. It maintains the triangular shape, which I think is important in defining the relative importance and effectiveness of each layer.

But the latest, and most aggressive, is via a tweet from Queen Anne Greenways.


All of the different versions have the same purpose:


Although the language of QAGreenways is the most straightforward and extreme, especially starting with a "BAN CARS", it's not so simple. It is setting up an order; if you can't ban cars, then promote walking, biking and transit. Separate them from cars. Enforce the rules. Then, last of all, bring out the shame flags and helmets.

bridgeport flagsCity of Bridgeport/Public Domain

Of course, that's not the way it works in real life; it is cheaper and easier to buy a pile of flags than it is to fix a road – and who wants to slow down drivers anyway? But if we are going to stop people who drive from killing thousands of people who walk or bike every year, then we have to turn our thinking upside down.

What is the Hierarchy of Controls, and what does it have to do with bikes?
It tells us that we are doing the wrong things first because they are easy.

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