Friday, October 25, 2013

UC Study: Riding a bike in SF more dangerous than we thought


The NY Times story the previous post is based on includes this:

Dr. Rochelle Dicker, a trauma surgeon at the University of California...cares for victims of the worst bicycle injuries, people who might need surgery and often end up in intensive care. So she decided to investigate those crashes. She and her colleagues reviewed hospital and police records for 2,504 bicyclists who had been treated at San Francisco General Hospital. 

She expected that most of these serious injuries would involve cars; to her surprise, nearly half did not. She suspects that many cyclists with severe injuries were swerving to avoid a pedestrian or got their bike wheels caught in light-rail tracks, for example. Cyclists wounded in crashes that did not involve a car were more than four times as likely to be hurt so badly that they were admitted to the hospital. Yet these injuries often did not result in police reports---a frequent source of injury data---and appeared only in the hospital trauma registry. Dr. Dicker is not a cyclist, but she said, “Lots of my colleagues do not want to ride after seeing these injuries.” (emphasis added)

Dr. Dicker's study confirms what cycling experts say about "solo falls," though it found a lot more vehicle/bike collisions than expected.

The SFBC's favorite bike safety instructor, Bert Hill, tells us that 45% of all cycling accidents are "solo falls" and that only 18% involve another vehicle ("Mission: Not Impossible," Paul McHugh, Feb. 17, 2005, SF Chronicle). And John Forester: "When you mention cycling accidents, most people assume that you mean car-bike collisions, because this is the only kind they worry about. This is wrong, because car-bike collisions account for only about 12% of cycling accidents" (Effective Cycling, page 262). Robert Hurst, a long-time bike messenger and author, in his book on urban cycling, The Art of Cycling, tells us that collisions with vehicles "account for no more than about 15 percent of all cycling accidents" (page 161).

At my request, Dr. Dicker sent me a copy of her study, which found that cycling accidents are consistently under-reported in San Francisco (the study didn't include accidents outside the city):

Underestimation of crash rates results partly from a lack of recorded data on cyclist-only (CO) injury crashes, that is, crashes in which no contact is made with an automobile. Moreover, there is bias in both police-reported and hospital-reported bicycle crash data because less severe injuries are reported and treated less frequently.

The study compared the information that city cops use, from the Statewide Integrated Traffic Records System (SWITRS), with records from San Francisco General Hospital, "the only trauma center for the city and county of San Francisco." Police reported 3,717 bicycle injuries from 2000 to 2009, and SF General reported 2,504 bicycle injuries during the same period, and "55% of bicycle injuries treated at SFGH were not associated with a police report." Which means that cycling accidents in this city have been under-reported by more than 50% (The MTA's Collision Reports rely on SWITRS and the SF Police Department.)

This problem with the numbers is not new. The Bicycle Plan's Framework document discussed it back in 2004:

The collision data presented in this chapter...does not include the many unreported bicycle collisions believed to occur in San Francisco...For the last several years, the San Francisco Department of Public Health has been working on an injury data linkage project using hospital admission data. Currently, San Francisco General Hospital (SFGH) is not obligated to report bicycle injuries to the SFPD. This is left up to the injured parties. EMS (ambulance services) is supposed to report bicycle injuries, but many are not reported (page 6-12, San Francisco Bicycle Plan: Policy Framework).

Odd that this never got done after all these years. Why? A possible explanation: If accurate data on cycling accidents in the city is gathered, it would confirm what critics like me are saying---that riding a bike in the city is a lot more dangerous than either City Hall or the Bicycle Coalition admits. That would also show that the city's aggressive promotion of cycling---encouraging even children to ride bikes---is irresponsible.

And the study found that treating cycling accidents between 2000 and 2009 cost the city $36.4 million.

The Centers for Disease Control tells us this is a national problem:

While only 1% of all trips taken in the U.S. are by bicycle, bicyclists face a higher risk of crash-related injury and deaths than occupants of motor vehicles do. In 2010 in the U.S., almost 800 bicyclists were killed and there were an estimated 515,000 emergency department visits due to bicycle-related injuries. Data from 2005 show fatal and non-fatal crash-related injuries to bicyclists resulted in lifetime medical costs and productivity losses of $5 billion.

No post about the NY Times and cycling would be complete without citing its story on another danger for serious cyclists.


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20 Comments:

At 5:18 PM, Anonymous Anonymous said...

What is your vision for transportation within San Francisco as the population continues to grow?

 
At 5:22 PM, Anonymous Anonymous said...

What explains the 844 "reported" injury collisions between cars and people in 2011? How about the 17 people killed by vehicles in 2011? Should walking be discouraged, too?

 
At 6:33 PM, Blogger Rob Anderson said...

The collisions between cars and people and walking would be a different study, wouldn't it? This study was about cycling accidents in the city.

My "vision" for SF would involve being a lot more careful about development, instead of big dumb projects like Treasure Island, Parkmerced, the Market/Octavia Plan, and the UC project.

And not building a lot of housing that discourages developers from providing parking for all those new housing units. And investing in Muni that matches all the development, which is not being done now.

The city's dumb "smart growth," dense development theory is only going to make traffic---and life in this city---a lot worse than it has to be, as the bobbleheads in City Hall implement the half-baked theories now fashionable in planning circles.

 
At 7:13 PM, Anonymous Anonymous said...

In other words, Rob's vision for San Franscisco is: stop building new housing and hope people just go away.

 
At 8:34 PM, Anonymous Anonymous said...

You neglect to mention that the intro to this story is about someone who crashed going into a corner at 35 MPH. This story is about cycling as sport, not cycling down Market Street at 10 MPH to get to work.

You might as well be saying that driving is dangerous by looking at the fatality rates of NASCAR drivers.

Shithead

 
At 8:52 PM, Anonymous Anonymous said...

“Lots of my colleagues do not want to ride after seeing these injuries.”

I wonder if any of her colleagues saw someone come into the ER after a car accident and swore off driving. "That's it - no more driving." Sounds a bit ridiculous, doesn't it?

 
At 10:19 AM, Blogger Rob Anderson said...

"In other words, Rob's vision for San Francisco is: stop building new housing and hope people just go away."

No, what I'm saying is that simply building a lot of new housing in big projects---Treasure Island, Parkmerced, the Market/Octavia Plan, the UC project, etc.---won't reduce housing prices; it will just make traffic worse than it should be.

Even as the city gives a green light to developers and encourages even more population density, it's making driving on city streets more difficult for everyone, a prescription for future gridlock.

City Hall's vision for San Francisco: build a lot of housing and hope all those new residents will ride bikes and not drive cars.

 
At 11:44 AM, Blogger Rob Anderson said...

"I wonder if any of her colleagues saw someone come into the ER after a car accident and swore off driving.'That's it---no more driving.' Sounds a bit ridiculous, doesn't it?"

Remedial reader alert: You ignore this message from the Centers for Disease Control in the post:

"While only 1% of all trips taken in the U.S. are by bicycle, bicyclists face a higher risk of crash-related injury and deaths than occupants of motor vehicles do."

 
At 8:46 PM, Anonymous Anonymous said...

No, what I'm saying is that simply building a lot of new housing in big projects---Treasure Island, Parkmerced, the Market/Octavia Plan, the UC project, etc.---won't reduce housing prices; it will just make traffic worse than it should be.

--> Wow Rob, you've re-written the entire basis upon which modern economic theory is based. Increasing supply does not actually reduce prices. Who knew.

 
At 8:48 PM, Anonymous Anonymous said...

"While only 1% of all trips taken in the U.S. are by bicycle, bicyclists face a higher risk of crash-related injury and deaths than occupants of motor vehicles do."

You also miss this.

"Drivers of small and mid-sized vehicles are 45% more likely to die in a motor vehicle accident than drivers of SUVs and large trucks"

We need to ban small cars. Now.

 
At 8:51 PM, Anonymous Anonymous said...

"While only 1% of all trips taken in the U.S. are by bicycle, bicyclists face a higher risk of crash-related injury and deaths than occupants of motor vehicles do."

The largest causes of death for adults in the United States are all obesity related. Cyclists being more fit than those who rely on motor vehicles increase their risk of crash-related deaths, but they increase their overall lifespan significantly by having a vastly reduced incidence of heart disease, diabetes, and cancer.

You spend a lot of time trumpeting how your genetics will lead to you living a long life. But your forebears were more active than you and had a substantially better diet. With your waistline, you might as well have one foot in the grave already. Which is bad, because we need your comedy.

 
At 9:18 AM, Anonymous Anonymous said...

Makes sense, thanks Rob. No matter what terrible traumas doctors witness in the ER from automobile accidents, nothing could put them off from driving, since bike accident traumas are always worse.

 
At 9:22 AM, Anonymous Anonymous said...

http://www.sfgate.com/bayarea/article/Menlo-Park-couple-killed-by-alleged-drunken-driver-4925770.php

Said one doctor in the ER after ultimately failing to save the lives of the couple, "I'll never walk again. Not after what I saw happen in this case."

 
At 9:48 AM, Blogger Rob Anderson said...

"You spend a lot of time trumpeting how your genetics will lead to you living a long life. But your forebears were more active than you and had a substantially better diet. With your waistline, you might as well have one foot in the grave already. Which is bad, because we need your comedy."

In fact I spend no time at all "trumpeting" my genes. Your reference is apparently to my long-ago response to a nasty commenter---like you, of course anonymous---who hoped I would die soon. I pointed out that my mother was 94 when she died.

You'll be disappointed to learn that your reference to my waistline is way out-of-date, too, since I'm jogging again and have slimmed down quite a bit.

 
At 10:20 AM, Blogger Rob Anderson said...

"Makes sense, thanks Rob. No matter what terrible traumas doctors witness in the ER from automobile accidents, nothing could put them off from driving, since bike accident traumas are always worse."

The UCSF study showed that riding bike in SF is a lot more dangerous than anyone but me thought, since cycling accidents have until now been systematically under-counted. You try to change the subject to cars and ignore this from the Centers for Disease Control:

"While only 1% of all trips taken in the U.S. are by bicycle, bicyclists face a higher risk of crash-related injury and deaths than occupants of motor vehicles do."

The CDC must be anti-bike, right?

Last month I asked the MTA when their latest collision report will be published, since it's months overdue. They eventually responded---after I asked 311 and the Sunshine Task Force to help me get an answer---that they're waiting for more data used to compile the annual report.

The annual Bicycle Count is also due to be released.

My suspicion: In both reports, they are scrambling to digest the UCSF study while at the same time touting the great bike revolution in San Francisco.

City Hall sees getting a lot more people on bikes as an important---and inexpensive---way to deal with the city's traffic congestion.

The UC study confirms what I've been saying here for years: riding a bike is a lot more dangerous than either City Hall or the Bicycle Coalition is willing to admit.

It's simply irresponsible for the city to encourage what is essentially a very risky transportation "mode." They are even urging the city's children to ride bikes on city streets!

 
At 11:28 AM, Anonymous Anonymous said...

"They are even urging the city's children to ride bikes on city streets!"

As bad as that is, it gets even worse. They're even encouraging children to walk, which involves crossing the street, an extremely dangerous activity that kills dozens of pedestrians every year in San Francisco. The height of irresponsibility.

 
At 3:05 PM, Blogger Rob Anderson said...

Funny, but neither the CDC nor the American Association of Neurological Surgeons mention walking to school as a significant cause of injury.

 
At 4:10 PM, Anonymous Anonymous said...

"Two to three people are hit by cars every day on San Francisco’s dangerously motorized streets."

http://sf.streetsblog.org/2011/04/12/citys-pedestrian-crash-toll-dwarfs-preventative-safety-costs/

You are welcome to let your kids walk around Rob; as for me, I value my kids' lives a little more than that. Mine do not leave the house except in my up-armored Humvee, purchased from Iraq and shipped to San Francisco. True, it cost a lot to get over here, but my kids' lives are worth it.

 
At 7:57 PM, Anonymous Anonymous said...


You'll be disappointed to learn that your reference to my waistline is way out-of-date, too, since I'm jogging again and have slimmed down quite a bit.

That would explain the white dots on the sidewalks of D5 as your elephantine body has caused cracks in them, which the owners of properties must now fix.

 
At 12:47 PM, Blogger Rob Anderson said...

I understand why you're anonymous---you have nothing substantive to say---but why the nastiness? Answer: because I challenge your religion, BikeThink.

 

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