How dangerous is bicycling?

Posted: February 13th, 2015 | Columns, Featured, The Spoken Word | 6 Comments

Hutton Marshall

The Spoken Word

Biking is different for me now than it was as a kid. Back in the Texas suburbs during the ’90s, I would ride my little Huffy bike around the wide, empty streets of suburbia without bothering to notice which lane I was in or whose driveway I was racing across. The sun was shining every day, even at night. Helmets were for klutzes and “bike infrastructure” was a foreign, unneeded concept.

[Insert ominous “20 years later” cutaway]

Today, I live in a different biking world. In the bustling, urbatopia of San Diego, I never go out riding without a helmet, because when I ride, I pedal down streets crowded with cars, pedestrians, dogs, potholes and more cars, plus a few more cars.

While I don’t feel like it’s all that dangerous if the proper precautions are taken, some treat my decision to bike-commute like some kind of martyrdom. It may be true that bicycling is a slightly riskier endeavor than driving those popular steel boxes powered by exploding gasoline, but just how much more dangerous is it? And is there any avoiding it? [Warning: math ahead]

Let’s start with a study published in 2007 by the Johns Hopkins School of Public Health, which measured the likelihood of an accident based on one’s mode of transportation. The first thing I noticed from the study is that motorcycles are terrifyingly dangerous. Basically, when you get on a motorcycle instead of a bicycle, you’re 25 times more likely to get into a fatal accident. Of course, this ignores a lot of big factors that affect the likelihood of an accident, which we’ll get to shortly.

The study calculated that out of 100 million bike trips, 21 will result in a fatal accident. There will only be nine fatal accidents for the same number of car trips, which means that biking, despite being much safer than a Harley, is still more than twice as risky as driving, at least where dying is concerned. As a pedestrian, your odds fall somewhere in between the two: more dangerous than driving, yet considerably safer than biking.

When the study analyzes nonfatal accidents, motorcycles are still three times more dangerous than bicycles, and five times more dangerous than cars.

This isn’t to say any of them is a death wish. When we’re talking about a nonfatal motorcycle accident, the most common of the bunch, there’s only a one-in-10,000 chance that’ll happen when you hop on your hog. For bicycles, there’s about a 0.00003 percent chance of an accident, or roughly one in 30,000, every time you get on a bike.

So your odds of crashing on a bike are a lot higher than winning the California lottery (one in 175 million), but even if you biked to and from work every day for the last decade, the chance of you getting in a nonfatal accident would be about one in six.

Buses, by the way, are by far the safest way to travel in all regards, according to the study. So when in doubt, hop on the frequently stopping train to Safety Land on the MTS.

How are these accidents happening?

There are some pretty strong trends that show who’s getting in these accidents. In 2012, the National Highway Traffic Safety Administration released data on the 726 fatal bicycle accidents that occurred in the U.S. that year.

In 29 percent of the accidents, the biker was hit by a car, which was by far the most common cause for biker injury. Sixty nine percent of accidents occurred in urban areas, and 30 percent occurred between the hours of 4 – 8 p.m. (i.e. rush hour).

Men, who make up 76 percent of U.S. bike riders, accounted for 88 percent of the fatal accidents.

At the beginning of this year, Circulate San Diego, a nonprofit advocating for active transportation, released a study analyzing where bicycle and pedestrian accidents occurred in our fine city. Perhaps the most shocking revelation in the report was that residents living in disadvantaged communities were are 10 times more likely to get hit by a car than residents of other San Diego neighborhoods.

The study also found that 30 percent of pedestrian crashes occurred on just eight roads, the most dangerous being University Avenue.

What makes University Avenue so dangerous is in part revealed in a third study, published in the American Journal of Public Health, which analyzed hundreds of bicycle accidents in a six month span in Vancouver and Toronto. It found that the most dangerous roads to bike riders were those with wide streets, parked cars and no bicycle infrastructure (e.g. University Avenue).

Roads with bike lanes lowered chance of injury by 50 percent, and protected bike lanes reduced risk by 90 percent, which, for those immune to obviousness, is really, really good. The study also found that roads with downhill inclines, construction and streetcar tracks can increase risk by as much as 200 percent.

How to better your odds

First of all, when you ride a bicycle, you should wear a helmet. I know, you look like a dweeb. It’s inevitable, especially if you went out and bought one of those dome-shaped BMX helmets thinking it would look cool. Well you were wrong; it’s dweeby too, if not more so. (There’s nothing dweebier than trying unsuccessfully to avoid looking like a dweeb.)

The point is, in two-thirds of fatal bicycle accidents in 2012, the rider wasn’t wearing a helmet. Wear your brain bucket, folks. There’s a gross, real reason people call it that.

Screen Shot 2015-02-13 at 10.48.09 AMAlso, let’s talk about booze. Twenty four percent of bicyclists killed in 2012 had blood alcohol concentrations exceeding 0.08 g/dL, the legal limit for operating a vehicle.

A lot of people my age seem to share the sentiment that biking to a bar on a Friday night is a safe, responsible alternative to driving there. While it’s true that you’re unlikely to do significant harm to others while biking drunk, and the penalties if you get pulled over won’t be as severe, the idea that it’s eliminating risk can be a fatal folly.

Another piece of advice I received from a longtime bicycle advocate is to plan your route before you get on the road, otherwise you might accidentally find yourself on the side of the highway feeling like a soon-to-be mosquito on a windshield. Google Maps has a bicycle function that takes bike infrastructure and elevation into account when calculating a route.

Finally, and this isn’t necessarily on your shoulders, noble pedaler, San Diego needs to create a safer environment for bikers. The statistics show that improving bicycle infrastructure makes the biggest impact on increasing safety for bike riders. While SANDAG will begin installing a large network of bike ways throughout the city in the coming years, “it needs to happen faster,” as the aforementioned bike advocate stated plainly.

Just don’t get drunk and leave your helmet at home in the meantime. And stay away from University Avenue.

—Through a contest held by New Belgium Brewing, Hutton Marshall pledged to live car-free for a year and commute with a bicycle. Contact him at


  1. billdsd says:

    Even better, learn how to ride safely in traffic. The San Diego County Bicycle Coalition offers free classes every month.

  2. Hans Wangbichler says:

    If the most common cause of bicyclist fatalities is being hit by a car, maybe we should consider that those cars are being controlled by people.I believe the focus should be placed on preventing accidents, rather than surviving them. Wouldn’t it make more sense to take guns away from murderers than having people around them wear bullet protection? You can’t have a liquor store within 600′ of a school, yet bars can have parking lots adjacent to them, and in the case of Urban Mo’s, tear down a 100 year old home to make room for more potential DUIs each night, in the Uptown area. How dangerous is bicycling? How dangerous is exercise? How long will we tolerate, as a society, reckless driving?

  3. roger says:

    If you read the book, “traffic: why we drive the way we drive” parked cars cause other drivers to slow down thus why a bit safer for pedestrians. But then the dooring issue comes up, making a cycle track necessary.

    Do not avoid University Avenue as that will show there is no interest for bikers to use it, as sandag installed bike counters in the roads

  4. Shirley Christian says:

    In Hutton Marshalls article “How dangerous is bicycling?” it seems to me there was a glaring omission. He failed to mention how so many bicyclists simply ignore the rules of the road assuming they have some special exemption from stopping at lights or stop signs whenever they choose. I watched a family of four cruising through a stop sign one day in Hillcrest and wondered what kind of an example this was for those kids. And I can’t count how many bicyclists I have watched do the same, one of which I almost hit because he came careening through a stop sign in front of cars, just because he could. Frightening. It is my understanding that bicyclists are to obey by the same traffic rules as cars. If they want the respect of automobile drivers, they need to respect the law as well.

  5. […] this article written by the editor of the SD Uptown News to be quite informative and helpful [see “How dangerous is bicycling?” Vol. 6 Issue 4], it neglected to address two pertinent issues regarding safety and […]

  6. I think the better question is “How Dangerous is Driving a Car”. A car is a 2000 pound piece of metal projectile traveling at 30-40 mph on a street (i.e. a lethal weapon) where people are walking, bicycling, skateboarding, etc. What are your chances of hitting, injuring, or killing a person when behind the wheel of a car? Cars must always take ultimate responsibility because they are the least vulnerable. Those who are most vulnerable need to be the most protected.

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