Saturday, February 14, 2015

The city's "high injury corridor" strategy

CDC: 515,000 emergency department visits 
due to bicycle-related injuries

Below is my latest exchange with the city about how its counting---or not counting---accidents on city streets. Instead of the informative annual Collisions Reports the MTA used to issue, we now get these "high injury corridor" maps that provide neither injury totals nor any analysis of specific streets to determine exactly where or why accidents happen. That apparently means we will no longer have separate accident totals for cycling, pedestrian, and motor vehicle accidents. 

At least Ms. Sarieh admits the problem presented by those UC studies

We are aware of the previous studies linking police and SF General Hospital data which found that approximately 20% of pedestrian injuries and 25% of total cyclist injuries in those datasets were not included in police records.

By lumping all accidents together in these "corridors" the city doesn't have to admit the obvious about its campaign to promote cycling: that riding a bike in San Francisco is a lot more dangerous than they and the Bicycle Coalition have been telling us for the last ten years. Apparently we will no longer be given accident totals showing an increase in cycling, pedestrian, or motor vehicle accidents. That will allow City Hall to continue pretending that riding a bike in the city is simply a green, win-win deal for everyone, including even the city's children.

The city can now claim that any street in the city they want to "improve" for cyclists---against the interests of more than 96% of those who use city streets---is a "high injury corridor" because, you understand, it's all about safety:

From: Rob Anderson 
Sent: Thursday, February 12, 2015 11:31 AM
To: DPH, PublicRecords (DPH)
Subject: Polk Street

Ms. Sarieh:

So your department doesn't have a "study" as such that supports the notion that Polk Street is a "high injury corridor." Instead, you created those maps from the location of previous accidents on city streets, which, by the way, makes most of the city's streets look like "high injury" corridors. 

You are probably aware of the controversy about how the city counts accidents after that 2012 UC study found that the city has a seriously flawed method of counting cycling injury accidents.

The question is, How/where did you get those numbers? Do those numbers represent accident reports from both the SFPD and SF General Hospital?

Regards,
Rob Anderson

The response to my message:

DPH, PublicRecords
to me

Mr. Anderson,

The high injury network accounts for 12% of city streets, or 125 miles, where traffic-related injuries---particularly severe and fatal injuries are most concentrated.

Over 70% of severe and fatal injuries to motorists, motorcyclists, pedestrians and cyclists on San Francisco streets occurred on this network.

This is based on data provided by the Statewide Integrated Traffic Records System (SWITRS) maintained by the California Highway Patrol based on police reported collisions for 2008-2012, the most recent available annual data. Similarly high proportions of reported fatalities for 2013 and 2014 also occurred on this network.

The methodology used to identify this network was created by the SFDPH, and first used to identify the pedestrian high injury network as documented here.

The same approach was used to expand the network to the Vision Zero high injury network to include all transportation modes including motor vehicles, motorcycles, and cyclists.

We created this network based on the best available location-specific data. We are aware of the previous studies linking police and SF General Hospital data which found that approximately 20% of pedestrian injuries and 25% of total cyclist injuries in those datasets were not included in police records. To address that data gap the SFDPH has hired an epidemiologist who is now working with SFGH as well as SFMTA and SFPD to develop a comprehensive transportation-related injury surveillance system that will include both police and hospital data to ensure accurate, coordinated and timely monitoring of injuries and fatalities for safety project prioritization, evaluation, and reporting.

Nancy Sarieh │ Public Information Office
San Francisco Department of Public Health│101 Grove Street│415.554.2716

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1 Comments:

At 10:00 AM, Blogger Rkeezy said...

Epidemiologist. The ones who track and study the spread of diseases, right? Makes sense, totally qualified.

 

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