Friday, September 30, 2011

On counterproductive laws

I came across this post last week on the Marginal Revolution blog, and I was completely intrigued. It has to do with highway speed limits, and the tension between what's best for safety and road design and what's best for police department coffers. In blogger Alex Tabarrok's words,
The 55 mph speed limit was a vain attempt by the Federal government to reduce gasoline consumption; initially passed in the 1974 Emergency Highway Energy Conservation Act the law was relaxed in 1987 and finally repealed in 1995 allowing states to choose their speed limits. Highways and cars are safer today than in the 1970s and on many highways speed limits were increased to 65 mph. Higher speed limits are often safer because what is worse than speed is variable speed, some people driving fast and some driving slow. When the speed limit is set too low you get lots of people who safely break the law and a few law-abiders who make the roads more dangerous.
That's a fair point by Tabarrok, and it's got empirical evidence to support it. Unfortunately, cash-strapped police departments typically don't like higher speed limits, because they often depend on ticket-writing to fund their operations. Tabarrok cites a specific example on Massachusetts' Route 3, a road I've driven on frequently (emphasis mine).
The speed limit on Route 3 is 55. The speed limit used to be 60... It was reduced by executive order in 1973 to comply with the national speed limit. When the national speed limit was repealed in 1995 the highway commissioner ordered the low limit retained because he was afraid the state would be sued or otherwise embarrassed...
It gets better. Route 3 was completely rebuilt a decade ago. The design speed for the project was 110 km/h (68 mph). The design speed is like a warranty: nothing in the road design requires a driver to go slower than 68 mph, not even on a wet road at night (the design conditions).
The average speed is not far from the design speed. The 85th percentile speed, which is supposed to be used for setting speed limits, is around 75 mph. A little over by my measurement, which found 1% compliance with the speed limit.
Eventually the absurdity of the 55 mph speed limit sunk in and in 2006 MassHighway traffic engineers recommended a speed limit increase. State Police vetoed the change, preferring the 99% violation rate that let them write tickets at will. Police have no legal role in setting speed limits. Somebody in the Romney administration weighed the risk of losing ticket revenue against the risk of being blamed for accidents. Police won.
After engineers lost that fight people began to worry about the high accident rate on Route 3. The state hired a consultant to do a Road Safety Audit. The consultant’s report blamed the low speed limit, among other factors, for the high crash rate. The report explicitly recommended raising the speed limit.
Three years later, state officials have not followed the advice of their engineers, their consultant, or 100,000 drivers per day. State police are still out there running speed traps and helping keep the road as dangerous and profitable as they can.
So when the state sign says obey the speed limit for safety, that is not just a lie but a malicious lie. It is a statement made with knowledge that it is false and with reckless disregard for the consequences after being warned of those consequences.
Yeah... that's not good. You'll often hear the line uttered that "speed kills", and to a point it's certainly true--excessive speed is absolutely not safe, under any circumstances. But it's also true that artificially low speed limits kill, whether or not anyone wants to officially admit it. There are many roads down here in rural Virginia where the speed limit is almost comically low, and the clear reason is to line the coffers of counties with otherwise very small tax bases. Safety is a secondary concern, and sometimes in fact a casualty of the low-speed-limit policy.

It's one thing to sell a policy (or a speed limit) based on "safety" when your real reasons lie elsewhere. It's quite another when that policy actually exacerbates the problem that it purports to solve. This is not government at its best...

[Marginal Revolution]
[National Motorists Association]

No comments:

Post a Comment