Lower Speeds Mean Safer Streets
20mph Zone in London Credit: Alan Stanton’s Flikr
Hard to think of a more obvious headline, right? Well, somehow this nugget of common sense has yet to catch on in American cities nationwide, where speed limits inside dense areas remain dangerously high at an average of 28 m.p.h. And astonishingly, speed limits New York, America’s most densely populated city, are a lofty 30 m.p.h. This is, in all honesty, fairly crazy, and I would argue that it led directly to the 256 traffic deaths suffered by New York City in 2009 (sadly, the lowest number since 1910). It’s important to remember that the chance of death by automobile increases exponentially with the vehicle’s speed:
* 5 percent of people die when struck by a motorist going 20 mph
* 45 percent of people die when struck by a motorist going 30 mph
* 85 percent of people die when struck by a motorist going 40 mph
* When cars exceed 20 mph, the comfort level of cyclists and pedestrians drops significantly
* Eye contact between drivers, and between drivers and pedestrians, drops rapidly at speeds greater than 20 mph
* Driving 20 mph requires a stopping distance of 150 feet, driving 30 mph requires a stopping distance of 200 feet, driving 35 mph requires a stopping distance of 250 feet.
Those stats can’t be repeated enough. Considering the incidence rates of car-pedestrian collisions in urban environments like New York, it’s almost unconscionable that speed limits remain high enough to allow for a 45% chance of fatality.
This is one of the prime reasons that the U.S. suffers much worse traffic safety than does Western Europe, which has been lowering speed limits in its urban cores for years now. In fact, London has been experimenting with 20 m.p.h zones for the past 20 years. A recent article from the British Medical Journal now shows what a success that policy was, lowering traffic casualty rates in the 20 m.p.h. zones by 41.9% and even by 8% in adjacent areas.
And London isn’t the only city pursuing such aggressive pedestrian safety measures. The cycling and walking meccas of Amsterdam and Copenhagen both have many 30 k.m.h. zones and Barcelona has followed suit with 50 k.m. of city roads designated as “Zone 30s” with another 165 k.m. set to be identically designated.
We’ve seen a lot of progressive transportation policy come out of the Bloomberg administration, but a reduction in city speed limits in even the most congested areas of Manhattan has not yet been discussed. Let’s hope there’s room in Bloomberg’s third term agenda for such street safety improvements that have already proved so effective for many great cities.
H/T: Tom Vanderbilt
James in Bronx, NY on Tue, Feb 23, 2010 at 1:49pm
It’s not enough to simply lower the speed limits. It’s an issue of enforcement as well. New York has a macho driving culture in which aggressive road behavior that would lead to a summons elsewhere is instead tolerated by the NYPD. I’m talking about stuff like weaving violently between lanes, rolling through red lights a half second before they turn green, blocking the box, tailgating, honking, and other bullying behavior. New York’s streets stand apart from the civil society that we all see every day on the city’s buses and subways. Who will finally take this giant quality of life issue on? With all the push for livable streets, bike commuting, etc in this city, it’s high time.
independentblogger on Fri, Mar 12, 2010 at 1:14pm
Reducing a few peoples’ deaths is a good goal. But we also need to balance that against everyone else’ need to get to work/school/grocery and whatever else in a reasonable amount of time. Reasonable people like us should be able to think of a way to reduce deaths, without increasing commute times.
Rather than making cars drive at an unreasonably slow speed and rather than allow senseless pedestrian deaths, I advocate speed limits should be *raised* to 40 mph and pedestrians and cyclists should be kept on the sidewalk where they belong.
Eliminating Jay-walking, and cycling in the street. would reduce those deaths just as effectively (by taking cyclists and pedestrians out of cars’ way) and it wouldn’t slow down the people who live on these city blocks - and drive them most frequently.
IB
James in Bronx, NY on Tue, Mar 16, 2010 at 11:27am
I don’t know where you live, but most people in NYC do not own cars. Therefore, “everyone else’s need to get to work/school” is accomplished via walking, biking, and public transit. For walking and biking, the most obvious safety hazard faced by far is that posed by motor vehicles. Mixing cyclists and pedestrians is not only asinine, but flat out dangerous for users of either mode. Please come back when you have some fully formed ideas.