Saturday, January 08, 2011

City streets are getting safer

This morning's Chronicle has another scare story on death and injury on SF's streets: "S.F.'s dubious No. 1---traffic deaths." But putting this story in context---using the figures in the city's annual collision reports---it's clear that city streets have actually been getting safer over time.

From the Chronicle's story:

An analysis of 2009 traffic accident statistics by the state Office of Traffic Safety shows San Francisco has more deaths and injuries caused by vehicular collisions than any other California city with a population of 250,000 or more when calculated by the number of miles driven. When the calculation is done on a population basis, San Francisco is seventh of the 13 cities. San Francisco also ranks first in the number of victims killed or hurt in accidents involving pedestrians, bicycles or motorcycles---and that distinction is true in rankings by miles driven or by population.

That seems alarming until you look at traffic deaths in SF since 1915 and learn that there's been a steady reduction in fatalities. From an average of over 100 deaths per year in the 1940s---the worst year was 1945 when there were 156 people killed on city streets---and in the 1960s, the number has declined to 35 in 2008. Over the ten years from 1999-2008, there was on average 44 traffic deaths a year on city streets (pages 5-7, "New York City's Pedestrian Safety Study and San Francisco Data," October 21, 2010).

In San Francisco a higher percentage of fatal collisions are pedestrian-related compared with other major American cities...Most of the variability in the annual fatality total in the past decade has come from the pedestrian total, not from changes to the vehicular fatal collision total (which have been in the range of 13 to 16 annually). Bicycle fatal collisions had remained in the range of one to two a year until three fatal crashes were reported in 2008. After 2004 annual fatal collision totals below 30 have started being more common, a possible indication of an improving trend.

Still sounds pretty dangerous for city pedestrians, until you consider that a lot more people walk in SF than in other cities. On page 11 of the report, there's a chart showing that, when you calculate "Pedestrian Injury Collisions per Walk Trips to Work in California Cities with more than 250,000 Population," only Anaheim is safer than SF for pedestrians (Only L.A. has more "annual work walk trips" than SF, which has 10,491,404): "Central cities like San Francisco can be much more active during the day, so using population figures from the U.S. Census can underestimate actual levels of traffic and pedestrian activity." There are simply a lot more people walking on our streets than in other cities.

As the latest "San Francisco Transportation Fact Sheet" of November, 2010, tells us, the estimated population of SF of 818,163 swells to 945,480 during the day, with thousands of non-residents commuting into SF. During a typical workday, there's also an increase of 35,400 vehicles on the streets of the city, and SF itself has 9,936 registered vehicles per square mile.

After New York City, San Francisco is the most densely populated city in the country:

The only consolidated city-county in California, it encompasses a land area on the northern end of the San Francisco Peninsula, giving it a density of 17,323 people/mi² (6,688.4 people/km²). It is the most densely settled large city (population greater than 200,000) in the state of California and the second-most densely populated large city in the United States.

Despite this population density and the number of motor vehicles in the city, San Francisco is safer than---wait for it---Copenhagen! And only a little more dangerous than that other paradise for cyclists, Amsterdam!

The city continues to struggle with the Muni system, but we should give City Hall credit for steadily making our streets safer for everyone over the years in spite of the number of people using city streets.

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