On average, vehicles seriously injure or kill someone in New York every two hours; last year, 173 pedestrians were killed. Last week Gov. Andrew M. Cuomo signed a bill allowing New York City to enact a citywide default speed limit of 25 miles per hour as part of its “Vision Zero” campaign to reduce traffic deaths to nil.
When the speed at which a car strikes a pedestrian rises a mere 10 m.p.h. — to 40 m.p.h. from 30 — the chance of the pedestrian’s dying rises to 85 percent from 45. The real question is not absolute speed but appropriate speed.
There are two surefire ways to reduce speed: the speed bump which costs little and is effective in a blunt, limited way. The other, though still relatively rare in the United States, is ubiquitous elsewhere in the developed world: the speed camera.
• Unlike most traffic enforcement, cameras work because they are visible and predictable.
• Install them, and give drivers warning, and speeds will drop.
• Random enforcement provides a very weak feedback signal — when a strong signal is needed to curb habitual behavior
• Driving fast without being caught or crashing — determines “how your brain decides whether to remember a habit for the future.”
• Speed cameras have been shown to reduce crash and fatality rates.
• A majority of people support speed cameras when they are used in school zones, on roads with a history of crashes or where many drivers violate the speed limit.
• The use of cameras does raise legitimate issues about privacy, transparency and accuracy, but similar concerns exist with any form of enforcement.
In any case, enforcement — whether by cameras or cops — cannot deliver “Vision Zero.” To alter driver behavior on speeding, a city like New York will need more than a catchy slogan, a technical fix or ramped-up enforcement. Enter “psychological traffic calming.”
This approach relies on the suggestive power of context: Drivers tend to go at a speed that feels appropriate for the road they are on. For instance, does your street have a center dividing line? If so, add a few m.p.h. to the average traffic speed. Is it one-way? Add some. Does it have well-marked bike lanes? Cut a few m.p.h. Trees on the side? Drop some.
The effect of psychological traffic calming seems contagious and painless. Drivers can be nudged out of their worst instincts.
Read the original article in its entirety.
