Tuesday, October 14, 2008

Reason #3. This measure will not increase pedestrian safety.

One of the more specious arguments that the RIFTies have made in support of Proposition T is that passage of this measure will make the streets safer for pedestrians. The theory is a simple one: less commercial=less traffic=fewer pedestrians killed. Indeed here is what the Prop T proponents have argued:

"....Prop T will make our city more safe, not less, by reducing the growth in city traffic. ... Traffic is making our city less safe in tangible and dangerous ways. Pedestrians are killed by vehicles on our roads at more than twice the national and state averages, a rate that has increased with traffic congestion..."

There's just one problem with this statistic, Santa Monica has way more than twice the amount of pedestrians than the national average, and pedestrian activity has increased faster than traffic congestion. For this to be a fair measure, one has to look at fatalities/pedestrian a number that is not tracked very well, since most cities do not factor pedestrian counts as part of their traffic counts.

When it comes to pedestrians, the truth is, it's not the amount of traffic that's important, it's the velocity of that traffic. To quote a 60's phrase, "Speed kills." And that's particularly true when a moving vehicle hits a pedestrian.
"Traveling at 40 mph, the average driver who sights a pedestrian in the road 100 feet ahead will still be traveling 38 mph on impact: driving at 25 mph, the driver will have stopped before the pedestrian is struck." (Source: McLean AJ, Anderson RWG, Farmer MJB, Lee BH, Brooks CG. Vehicle Speeds and the Incidence of Fatal Pedestrian Collisions - Volume 1. Federal Office of Road Safety, Australia.)
As the chart below indicates, a pedestrian struck by a vehicle going 20mph has a 95% chance of survival, (and 30% suffer no injuries) whereas that same pedestrian struck by a car going 40mph has roughly less than a 20% chance of making it home alive.

(Source: Limpert, Rudolph. Motor Vehicle Accident Reconstruction and Cause Analysis. Fourth Edition. Charlottesville, VA. The Michie Company, 1994, p. 663)

So that would lead one to think that we should focus less on the quantity of traffic, but the need for traffic calming, i.e., for streets to be configured so that cars naturally go slower. Ironically, traffic itself, can be a great traffic calmer, as are street trees, parallel parked cars, and an active retail environment. But to prevent that traffic from spilling over to neighborhood streets look at the example provided by the City of Berkeley's traffic calming plan (below) for the Willard /Bateman /LeConte Neighborhood. You'll see many devices in use such as street narrowing, traffic circles (in green), and pinch points (opposing yellow triangles). Other options include short medians as Santa Monica has used north of Wilshire between 2nd and 4th streets and even "woonurfs," (a Dutch term for streets with a contrived s-curve along the length of the block to slow traffic)

Sometimes even signage can help. Look at this example marking a residential street in the Netherlands. Of course that sign comes with a host of other traffic calming measures that support the idea that this is not a street on which to speed.

So, once again, when we drill down to the issue at hand, in this case, pedestrian safety, we see that there are lots of tools in the box than can and should be used. Proposition T is not one of them.

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