Safety Theatre | WalkSydney

I posted a piece on WalkSydney: Safety Theatre.

What do the following things have in common:

Bicycling in Amsterdam is safer than Sydney, yet there are no helmets in sight. Instead there are separated bikelanes and a better culture, as well as safety-in-neighbors.

• Bike Helmets

• Sharrows

• Marked Crosswalks

• Fining Pedestrians

They are designed to make people feel safer than they are. The natural reaction is a misjudgment of actual risk due to risk compensation. The result is that people don’t behave safely enough, which makes it more dangerous.

In contrast, when people feel less safe, they behave in a safer way, which improves safety compared to normal behaviour in the same circumstances.

For instance in the controversial case of bike helmets, I am not saying if you are dropped on your head, wearing a helmet doesn't reduce the chance of your head splitting open. I am saying it increases the likelihood of being dropped on your head. The total risk of your head being split open is the product of these two factors:

P(HeadSplitOpen)=P(DroppedOnHead)*P(HeadSplitOpen|DroppedOnHead).

Helmets are associated both with P(HeadSplitOpen|DroppedOnHead) decreasing and P(DroppedOnHead) increasing. How this nets out is an empirical question, whose answer varies depending on context.

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