Wednesday, April 2, 2014

San Francisco Vision Zero: vehicle speed

San Francisco's Board of Supervisors embraced a "Vision Zero" policy goal which is gaining traction: the goal is for zero pedestrian and cycling deaths within 10 years.

It sounds good, but it's a bold goal which demands real action. It's like San Francisco's "Transit First" policy, a part of the City Charter, which states that the pedestrian safety and public transit receive priority over individual motor vehicles. But in the end, there's little evidence this law drives actual policy. Lip service without action reeks of hypocracy, and hypocrisy is in no shortage in San Francisco. "Leland Yee". Nuff said. '

But assuming Vision Zero is serious, there's only one way for San Francisco to substantially reduce the carnage seen on the roadways year after year: reduce vehicle speeds.

A classic example: Potrero Ave near Potrero Hill where I live. It's signed for a 25 mph speed limit, appropriate for a road with a school, a hospital, and a large number of homes. But the 25 mph posted limit is a farse. Speeds more typically exceed 40 mph on the road, popular as a bypass for Interstate 101 when the freeway is clogged at Hospital Curve, which is often.

Another example: San Francisco has dense grids of streets where traffic is typically halted every block by stop signs or traffic signals. These blocks are short. Yet it's common for drivers to floor the accelerator, then slam on the brakes just in time to slow to what they perceive is a reasonable imitation of stopping. Such neck-snapping accelerations and decelerations do little to reduce travel time but do a lot to increase fuel consumption and reduce pedestrian safety. Really it's driven more by testosterone than rational thought. These people need to get out of their cars and exercise more. Then they'd have a healthier outlet for their aggression.

People like to talk about the three E's: Education, Enforcement, and Engineering for public safety. The Education part is no-brainer: the speed limit is as fast as you should go. That's simple enough. That's not working so well. Engineering suggests traffic calming, but it's prohibitively expensive and slow in the bureaucratic quagmire which is San Francisco. The real key is enforcement. But the present model for enforcement is not the solution. Police are paid with salaries well in excess of $100k per year, with generous benefits and pension programs no public sector industry can come close to affording. They're expensive, to put it lightly. And they have little interest in spending their time flagging down ubiquitous speeders. They consider themselves overqualified for such mundane tasks.

So we need another way.

That way is obviously automated enforcement. If your car exceeds the speed limit by some combination of speed and time, a citation goes to the registered owner of that car. That's it. Do that, and speeding will disappear virtually immediately.

The problem is the law won't allow for such a policy. First, the speed limit is restricted by the interpretation of the "prima facie speed law", which says that traffic isn't allowed faster than the maximum safe speed "as determined by a traffic survey". The problem is that's interpreted to mean the prevailing speed of traffic, which is measured by the 85th percentile speed determined in traffic surveys. That means if 20% of the cars on Potrero Ave are doing 50 mph in the 25 mph speed zone, then you can't be ticketed for doing 40 mph in that 25 mph zone, whether or not that speed is compatible with Grandma in her walking getting across the road alive.

So for safety-driven speed limits to be enforceable, the 85th percentile rule, in place due to car-loving Southern California, needs to go. This law is based on a more universal engineering principle which should also be retired.

Next is the rule that the driver of a vehicle needs to be positively identified in order to be cited. This rule is inspiration for hit-and-run drivers across the state to hit the accelerator after they run down pedestrians and cyclists. Even if their car is ID'ed, if they can provide a reasonable doubt they were driving, they not only avoid criminal charges, but keep their driving licenses. That needs to end. If you have a registered car, as is the case with a registered gun, you have responsibility for fines accrued by users of that car. This is already the case in Europe, for example, and it's already the case for bridge tolls and parking violations. Driving is a privilege, not a right. That means for traffic citations, the standard of proof is not the same as it is for misdemeanors and felonies. If you're car is speeding, you should be held accountable.

Then there's the speed limits themselves. In San Francisco, a compact city with dense population, there's simply no good reason for cars to be driving in excess of 25 mph except on the freeways which nature hasn't had the wisdom to destroy yet (the 1989 Earthquake did SF a huge service by taking out the Embarcadero Freeway. A targeted strike on 280 would be even better). The difference between 40 mph and 25 mph for a 7-mile drive across the city, assuming that speed can be maintained for half the distance (the other half of the distance congestion-limited) is 3 minutes and 10 seconds. Thats it. That's a very small price to pay for the huge safety advantages of a 60% reduction in vehicular kinetic energy associated with that speed reduction. So a city-wide 25 mph speed limit is appropriate. Even 25 mph is 5 mph more than the "20 is Plenty" program in London.

Unfortunately this all requires primary action from Sacramento, the legislative capital of California. But San Francisco's state legislators should be leading the call.

Automated enforcement is already applied to commercial vehicles in Germany, for example. This is a good start, because if the commercial vehicles were going 25 mph on Potrero Ave, it would be hard for private vehicles to go much faster. Germany uses speed sensors attached to the axles for this purpose, sort of like old-style bike computers which use magnets to measure wheel rotation. But with GPS technology having reached a cost level of 10's of dollars, it would be easy enough to require new vehicles sold in the US to monitor their speed with GPS as well as a black-box function to provide evidence for behavior in the seconds leading to a crash. The conspiracy theorists would go ballistic at this suggestion, arguing the government would be monitoring their travel. First, government is too incompetent to monitor much of anyone. Look at 9-11. Second, the remedy is simple: take public transit, ride a bike, take a taxi, walk... there's other ways to get around without a personal motor vehicle

So this is the sort of seriousness Vision Zero needs if it's not going to be the usual "cost of doing business" road carnage into the forseeable future. I honestly don't believe there's the political will to do it, but I hope I'm wrong.

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