Study: SF’s Severe Traffic Injuries Have Been Heavily Underestimated

The number of severe traffic injuries inflicted on San Francisco’s streets has been grossly underestimated, according to hospital researchers.

In one year, more than 60 percent of San Francisco’s severe traffic injuries were not identified in SFPD reports — until now, the city’s sole source of injury data — according to a new study [PDF] by researchers at the SF Department of Public Health.

A woman injured by driver on Masonic Avenue in 2011. Photo: Matt Smith, SF Weekly

In the 12 months starting at the beginning of April, 2014, 515 patients were admitted for severe traffic injuries at SF General Hospital, site of the city’s only trauma center. Police reports only accounted for about 200 of those injuries.

A person is severely injured in SF traffic every 17 hours on average, said Leilani Schwarcz, the epidemiologist who led the study as part of SFPDH’s Vision Zero team. Of the 515 victims counted in the one-year period, 36 percent were pedestrians, 20 percent were bicyclists, 26 percent were motor vehicle occupants,  and 17 percent were motorcyclists. Sixteen died.

The study defined “severe injuries” as cases where the victim was hospitalized for more than 24 hours. Of those, 10 percent are admitted to a skilled nursing facility for long-term recovery, as was the case for Monique Porsandeh in 2013.

“Those are the people that are most likely suffering long-term disabilities and physically or mentally-life changing events,” said Walk SF Executive Director Nicole Ferrara, who said it’s “really shocking that there are so many more life-changing injuries than we thought.”

Schwarcz said the SFMTA funded the SFDPH study to develop a system that combines a range of data sources to more accurately assess the “true burden” of traffic violence. The agencies plan to conduct broader studies on the subject.

Researchers don’t know yet why so many severe traffic injuries have gone unreported. One possible reason offered by Schwarcz was that police officers “aren’t trained medical professionals” and can’t necessarily assess injuries fully. In addition, injuries sustained on freeways, which are outside SFPD’s jurisdiction, might not be counted. A small number of traffic injuries flagged by SFPDH may be due to solo bike crashes or collisions in BART tunnels, but not enough to account for a significant share of the discrepancy with SFPD’s numbers.

Police reports were “never intended” to provide the sole basis for assessing the extent of traffic injuries, said Schwarcz.

Roughly 800 to 900 pedestrian crashes in total are reported every year, based on police reports. SFPD researchers have long suspected that at least 20 percent of pedestrian injuries go unreported, based on the volume of injuries seen at hospitals.

In 2011, an SFDPH study found that pedestrian injuries impose a cost of about $76 million a year, $15 million of which is for injury treatment alone.

  • Foginacan

    Widening bike lanes is great if there’s room. In the case of Market Street, there is no excess room as it’s currently configured. Bikes also currently have the right to ride on streets, and technically, sidewalks.

    The problem is your thinking only works one way, in self interest. If there’s a traffic jam, should we reduce the bicycle lanes to re-accomodate cars? Where sidewalks are congested, should we reduce bicycle lanes to widen pedestrian access?

  • Alicia

    I asked if there was a speed limit. I didn’t ask if bicycles could break the automobile speed limit.

    For someone who protests you’re not a troll, you’re sure adopting troll-like tactics. You did not ask *if* there was a speed limit for bikes – you and I both know that there is. What you asked was, and I quote, ” Is there a speed limit the bikes are observing?” (Emphasis added.)

  • Alicia

    If there’s a traffic jam, should we reduce the bicycle lanes to re-accomodate cars?

    Not at all. Bicycles are smaller, and therefore a lot more people can get around in the same amount of space than could possibly get around in private cars. Same goes for public transportation. If you are really worried about congestion in your neighborhood, then maybe you should do your part and drive less- whether that means carpooling, taking Muni, walking or biking.

    Where sidewalks are congested, should we reduce bicycle lanes to widen pedestrian access?
    No, in order to accommodate those pedestrians, we should reduce car lanes, and/or parking lanes if there are any. As I stated a lot more times, it’s a more efficient use of space.

  • nhburdick

    Bicyclists (over 13) do NOT have the right to ride on sidewalks in SF actually — though this varies by county/State.

    Here are the specifics:

  • Foginacan

    Thanks, though I’ve read conflicting info (some bike advocates claim the opposite for SF). Both understanding and enforcement of laws needs work. I’m also not sure what I may have originally said that you were responding to.

  • NoeValleyJim

    Some sidewalks are dual use, but not very many. The Embarcadero is the main sidewalk where bicycles and pedestrians are both allowed. I wish it weren’t so though, it confuses people too much.

  • Alexander Vucelic

    bike lanes can carry 3-10 times the traffic versus private motorist lanes.

    bikes simply are more efficent than cars at moving people in a place like SF

    If one wants to seriously reduce traffic congestion in SF, then widespread conversion of car lanes to bike lanes is necessary.

    Bikes take up 8 sqft to park. Cars Parking Garages about 400 sqft per car. In SF, car parking is insanely expensive and inefficient use of scarce urban land.

    Cars are great in rural areas, but in SF not so much.

  • Foginacan

    My sense is you’re not familiar with SF, or it’s population.

    I guess we should evacuate the population who can’t meet your fantasy of “efficiency”? Oh, and not for nothing, but a lot of people using bike lanes also own cars for grocery shopping, and other tasks. They have to.

  • Jimbo

    hahahahhahahha. fairy dust land

  • Jimbo

    hes like in a fairy world. the vast majority of people iN SF own cars and 40% have 2 cars. there is a lot of commuting happening. bike lanes barely make a dent. what we need are transit improvements. we may hit 5% of commuters being cyclists by 2018. and 7% by 2025 even with new infrastructire.

  • Jimbo

    regardless of the situation, cars, buses, pedestrians, bicyclists are always the most important. very funny alicia

  • Alexander Vucelic


    bike commuters are about 10% of roadway traffic in SF today and growing by double digit rates.

    A 6′ bike lane has a capacity if more than 1,000 cyclists per, hour at a LOS of A or B. A 12′ car lane is gridlocked at 500 cars per hour. Is not Even close.

  • Alicia

    Ah, the troll comes back to spout more gibberish. Got it.

  • Alicia

    Don’t waste your time. Jimbo and Foginacan are living in denial of basic geometry and physics.

  • Alexander Vucelic

    they are scared of the future

  • @Foginacan – Which bike advocates, specifically? I have never in my life heard a bike advocate support biking on the sidewalk, even where it’s legal. (It is legal in most of the world, most of the nation, and most California jurisdictions, the main exceptions being specified business districts. It is not legal in San Francisco and nobody claims that it is.)

  • @NoeValleyJim – Yes, the Embarcadero is under Port Authority jurisdiction and the sidewalk there is a multi-use path (MUP). There’s another prominent example along Kezar Drive, indicated with brass bike stamps.

  • Note the differences between the Swedish approach and what we’re using the same name for here:

    The interest in Vision Zero is due to the success of the Swedish program. We should actually try that here instead of slapping a new label on old, failed strategies.

  • This can’t be THE STUDY!!!! because it doesn’t really support what Rob Anderson says it does.

  • Rebecca Gardner

    I gotta agree with you there.


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