Shocker: Speed Limits Are Useless Without Enforcement

Fatality_rates.gifIf drivers don’t acknowledge the risk of speeding, street designs and enforcement practices have to do it for them.

New research from Purdue University highlights the futility of controlling drivers’ speed with signs. The Times’ health blog has the story:

When it comes to speeding, many American motorists don’t worry about safety. They just worry about getting caught.

Those are the findings by researchers from Purdue University who
surveyed nearly 1,000 motorists about speed limits and driving habits.
They found that many drivers are cynical about the safety benefits of
driving within speed limits, and many think they can drive safely while
speeding as long as they won’t get caught, according to the report in Transportation Research Part F: Traffic Psychology and Behaviour.

"So the faster you think you can go before getting a ticket, the
more likely you are to think safety’s not compromised at higher
speeds," said Fred Mannering, a professor of civil engineering at
Purdue, in a press release. "For whatever reason, respect for speed
limits seems to have deteriorated."

The case for traffic-calming and automated enforcement is already strong. This makes it even more airtight. Drivers are basically ignoring posted limits on roads designed to accommodate speeding. (Traffic author Tom Vanderbilt wrote a great post last month about the multi-pronged wrongheadedness of this approach to street design.) Since drivers respond more to the threat of tickets than the inherent dangers of speeding, automated devices like red-light cams and speeding cams are essential to thoroughly deter this behavior.

In New York, the design part of the equation is improving while the enforcement component lags, thanks in large part to a police department that seems more
concerned with moving traffic than reining in reckless driving.

Effective traffic enforcement would be more manageable for NYPD if it weren’t for Albany. David Gantt, the Rochester Assemblyman who
killed bus-lane enforcement cams this June, has stifled red-light cameras for New
York and other cities for years. Evidence like the Purdue study has yet
to sway him.

The fact that this story was picked up by health reporters is an encouraging sidenote. Livable streets advocates will have powerful allies if public health authorities recognize unchecked speeding as the catastrophe that it is.

  • Boris

    I don’t think a survey of motorists in Tippecanoe County, Ind, can perfectly apply to New York City. Many pedestrian-free suburban and rural roads can handle significantly higher speeds than their posted speeds, but they have little in common with city streets.

    Also, speed limits for the same roads vary from state to state and country to country. Since any human’s reaction time is largely the same around the world, the differences have to do with education, sense of “what is prudent,” and politics. Better enforcement does nothing to influence any of those three issues.

  • Redesign the streets so you CAN’T speed.

    Not only will motorists murder fewer pedestrians in NYC, but I’ll murder fewer motorists.

  • Wow – I’d never seen the stats on that graph presented that way before. They’re pretty stark. NYC has more pedestrians than anywhere else… can’t we lower our speed limit from 50/50 to one in 20?

  • Ian Turner

    I think that drivers can speed without sacrificing safety, but only when they’re driving on the highway under good conditions in the middle of the Mojave. There aren’t any pedestrians to hit, and even if there were, there’s no real difference between 70 MPH and 100 MPH as far as fatality risk is concerned.

    That said, speeding in New York City, and especially on local streets, is a deadly scourge. It’s hard to respect drivers who engage in such antisocial behavior.

  • Niccolo Machiavelli

    Again Europe beats us like we stole something. In Germany there are no speed limits on the autobahn, there are rules but no speed limits. Get off the autobahn and speed and you have a very good chance of getting a ticket from the photograph. They came to our hotel room to make sure we got it when I was there for the World Cup.

    By the way, who won the World Cup again? Refresh my memory

  • Bernard Marx

    “Again Europe beats us like we stole something. In Germany there are no speed limits on the autobahn, there are rules but no speed limits.”

    Not exactly. There are _sections_ of many autobahns (no such thing as _the_ autobahn) that don’t have speed limits, but most of the highway mileage in Germany has speed limits (and both enforcement cameras and highway patrols). So far as I know, no other country in Europe has any speed-limit-free zones.

    “Redesign the streets so you CAN’T speed.”

    Taken a look at the budget picture lately? How many years do you think it’ll take before that has much effect? My guess would be about 300.

    Hate to say it guys, but the study cited here, makes it clear that what we need is enforcement, not engineering. These days, cars are so good (i.e., powerful, manoeuverable, easy to control, stable, well isolated from roughness) that even traffic-calming designs are unlikely to have much of a deterrent effect on speeders. Look at the way SUV drivers drive — weaving, passing, accelerating, stopping short. Anybody trying this stuff in, say a ’70s Ford Bronco would flip and die. Nowadays, people do things you used to only be able to do in a sports car in three-ton behemoths. Chicanes, neck-downs, speed humps? These aren’t slowing anybody down; that just makes it more fun for the idiots racing souped up Civics. Ever notice how you can be zipping along at 80 mph, then all of a sudden, everybody hits the brakes and starts doing the speed limit? Why? Because of a sign, or because they see an accident on the other side of the road, or because they enter a construction zone? No. Because they see a cop car on the shoulder.

    Enforcement is something we actually can afford. NYC is wildly over-policed, with thousands of cops devoted to tasks that reduce our level of freedom without enhancing our safety. The conversation should be about how to change policing policy. All this design stuff is great fun for the folks around here with planning degrees, but it’s largely irrelevent.

  • Ace

    By the way, who won the World Cup again? Refresh my memory

    The Phillies!

  • Read this BBC news: http://news.bbc.co.uk/2/hi/uk_news/7803997.stm

    Technology may be a solution here. Can we make it a law that all car must come with an auto-speed limit device.

    Driving a car without such control device will be illegal in the city.

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