Saturday, June 25, 2011

Transportation Fridays: The Psychology of Safety

by Betsy Harvey, MCRP '12
Last week I wrote about the shared streets principle in which regulatory devices such as stop signs and curbs are removed and pedestrians, bicyclists and drivers navigate the same space. In a controlled environment – your average road – drivers assume that risk is low. Therefore they are less likely to pay attention to what is happening around them – any place beyond their immediate travel lane – because they assume that everyone else is following the same rules.
The shared streets concept (or shared space, as it’s sometimes called) rests on the idea that taking away regulations makes streets safer, and the experiences of many Dutch cities (where the most extensive work has been done) bears this out. Check out this CBS news clip: http://www.cbsnews.com/video/watch/?id=5290564n
According to David Engwicht, the co-founder of the Australian-based Creative Communities International, there is a strong relationship between unpredictability and safety: the more uncertain the driving environment is, the safer it is. Safety depends not on the actual risk of the environment, but rather on the “perceptual actual difference” (PAD), commonly known a false sense of security. Your standard county highway on which there are few pedestrians or bicyclists may have fewer accidents than a busy street running through a downtown, but the false sense of security is much higher. The tightly-controlled road environment encourages drivers to feel the road is safer than it is, even though the actual risk is still quite high; therefore, the difference between the two, PAD, is high, and the road is more dangerous (see Figure 1).

Figure 1: Intrigue and Uncertainty: Towards New Traffic Taming Tools
Source:  Creative Communities International

The unpredictability of a busy street forces drivers to slow down, which is what the design of a shared street is meant to do. Visual clues, such as children playing in the street, tell motorists that they must expect the unexpected and slow down. Just as predictability increases PAD, unpredictability decreases it, making the busy street safer. Drive through Manhattan or downtown New Brunswick’s George Street, and you can’t help but to drive slowly and to look out for pedestrians. Drivers know to expect the unexpected; walkers and cyclists are notoriously bad at following street regulations. So the next time someone jaywalks or a biker is riding on the wrong side of the road, remember that by acting unpredictable they may be making streets safer for all of us.

Links for further reading:

More examples from across the world

Bain de Bretagne, France. Source: Wrington Website, North Somerset, UK

Lund, Sweden. Source: Hamilton-Baillie Associates

Newcastle, UK. Source: Hamilton-Baillie Associates

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