Of all the objections I get from people about why they can’t ride a bike to get around, perhaps the most frustrating is the claim that bicycling is too dangerous. According to this line of reasoning, we all need the protection of a two-tonne steel cage in order to survive the trip to the office or the grocery store.

I’ve always felt that this was complete bullshit, but I admit that my emotions may have been playing a part in this rapid condemnation as well. I started riding bikes about 32 years ago, and I just never stopped. To me, bicycling is being alive, and I’d rather run any necessary risk of death than be condemned to a life where cars were the only way to get around, because that sort of soggy dependence wouldn’t be much of a life to me.

But luckily for all of us, we don’t have to choose between safety and freedom. They both come together perfectly in the form of bicycle transportation, and once we work our way through the statistics of the matter, all talk of choosing cars over bikes because of safety can be banished from the face of the Earth – forever.



There’s going to be a bit of math involved, so for busy people we’ll begin with the final answer, then work through how we got there below.

Riding a bike is not more dangerous than driving a car. In fact, it is much, much safer:

Under even the most pessimistic of assumptions: Net effect of driving a car at 65mph for one hour: Dying 20 minutes sooner. (18 seconds of life lost per mile)

(18 seconds of life lost per mile) Net effect of riding a bike at 12mph for one hour: Living 2 hours and 36 minutes longer (about 13 minutes of life gained per mile)

In engineering and math, one method we use to prove a case is to define the boundary condition. If you can prove that your design holds up even in the worst possible case, it is guaranteed that it will work in all situations. So the box above is as bad as it gets. It’s already pretty good, so let’s see how we got there.

First of all, in the entire United States (Population about 310 million), there were only 623 cyclist deaths in the year 2010. For perspective, there were about 26,000 deaths due to each of “falls” and “alcohol”, and 35,000 caused by car crashes. So for every cyclist who dies on a bike, 56 die in cars. Out of the MMM readership alone (roughly 0.1% of the US population), 3 people die in car accidents every month.

But of course, we are a nation of Car Clowns, so as ridiculous as it seems, we cover a lot more miles in cars than on bikes. Still, we cyclists put in a good show given our small numbers, pumping out about Nine Billion Miles on our rippling leg muscles.

Dividing 623 into 9,000,000,000, we end up with a cycling fatality rate of about 6.9 per 100 million miles. According to the NHTSA, that same statistic is 1.11 for cars in 2010.

So on the surface, it looks like cycling in the US is about 6.2 times more dangerous than car-driving per mile (note that this is dropping as cycling grows in popularity – in the Netherlands, cycling risk is way down around 1 per 100 million). One of the goals of this blog is to help make the same thing happen here.

But we’re not done yet. First of all, let’s compare a cyclist at a comfortable commuting pace of 12MPH, with a car driver on the interstate at 75MPH. Now, the risk per hour is equal, because the car is covering 6.2 times more miles than the cyclist. So the accident risk per hour of the two activities is roughly equal. Many will complain about this comparison, but it is valid in the sense that cars encourage people to cover ridiculous amounts of ground each year for no good reason – an average of 15,000 miles per driver per year. So the average driver ends up much more likely to die than the average cyclist in a given year.

Exactly how big is the risk in a typical hour of cycling or driving? Let’s calculate it this way: the average MMM reader probably has about 55 years left in his or her expected lifetime (1.73 billion seconds) . Dividing this by the chance of trouble in each activity, each hour of driving or biking subtracts between 20 and 24 minutes from your expected lifetime due to the risk of accident.

But wait – we’ve so far neglected the whole reason I even talk about bicycling on this blog: because it is extremely good for you, and it saves you a shitload of money. It is not an exaggeration to say that a bicycle is a money-printing fountain of youth, probably the single most important and highest-yielding investment a human can possibly own.

How powerful is this effect? Consider this: for every hour of exercise you do, you extend your lifespan somewhere between 3 and 9 hours. So while the fatality rate above suggests that riding at 12MPH for one hour would shorten your expected lifespan by 24 minutes, you more than counteract that with a gain of at least 3 hours*. The net benefit of 2:36 is what you see in my box above. And that’s the worst case – it only gets better from there.

The years you do live will not only be greater in number. They’ll be healthier ones. How would you like to be packed with energy every day, rarely get sick, and be able to climb mountains and lift heavy things without fear of injury? What about being more attractive to people you would like to attract, more desirable to employers, having a clearer mind, and the ability to work harder? All of these are gifts that the bicycle giveth, even as the car taketh away.

What about money? Each hour of 12MPH bicycling also saves you about $5.00 in car operation costs (figuring cars at $0.50 per mile and bikes at $0.05). So that’s a minimum of $5.00 per hour of after-tax salary based on mileage alone.

Studies show that even mild exercise like riding 2 miles a day also saves you from missing about two sick days of work per year. Assuming your days are worth about $300, you spent 60 hours riding to earn $600. An additional $10 per hour. And how do we account for those extra 2.5 hours of life you gained? Since one of my rules is that your spare time is worth more than $25 per hour, you get another $62.50 in pay for each hour you ride your bike.

All-told, the net benefit is probably over $100 per hour, given the fact that being a cycling athlete makes you more productive, more attractive, more sexually capable, and better in every way than your old car-dependent self. And then there’s the joy of just getting out of that ridiculous clown apparatus and being a real human, powering your own transportation as you should be.

So that’s the worst possible case. It gets even better from here. Are you ready for a few final rounds of ammunition to fire into the limp corpses of the whining anti-bicycling complainers?

Remember the US cycling fatality ratio of 6.9 per 100 million miles? That’s with our current group of cyclists: a disproportionate number of children under 14 with no driver training, homeless people, DUI-convicts who have lost their license, competitive road racers and downhill mountain bikers, and the less than 1% of adults

In the box above, I used the minimum 3 hours for the life-extension estimate. In reality, it is probably closer to 5.

While already much safer than car-driving, cycling gets even safer as more people join in. Drivers become more aware of cyclists, and more bike lanes and dedicated paths get approved and built instead of Clownways. So you win, AND you change the world – every time you ride.

“But I’m still afraid. How about I drive my car to the gym, and then work out really hard there to extend my lifespan?” – not a terrible idea, but you’re missing the math here. Car driving shortens your lifespan. Bike riding extends it. You’ll be safer if you ride your bike to the gym and do that same workout.

– not a terrible idea, but you’re missing the math here. By saving so much money through biking, you are able to retire years earlier, potentially cutting out thousands of additional car-commuting trips to work. This improves your safety statistics even more.

And all this without even getting into the whole “Planet” issue. Sure, biking also solves most of the biggest problems facing developed countries – energy consumption, carbon output, climate change , urban sprawl, obesity, heart disease, depression, even wussypants mentality. But isn’t it amazing that the case is so strong even if you don’t give the slightest shit about the Earth?

Given these final adjustments to the data, I close the article with my own best estimates:

Biking vs. Driving Driving a car at 70MPH for one hour: 20 minutes of lifespan erased

$35.00 per hour of money burned Riding a bike at 12MPH for one hour: 4.5 hours of lifespan gained

$100 of monetary gains secured

On a Per-Mile Basis:

Car: Lose 50 cents and 18 seconds of life

Bike: Gain $8.33 and 1350 seconds of life

Regardless of how you tweak the stats for your own personal situation, the case for cycling over driving is so enormous that it would be difficult to even put them on the same level. Can you afford to take the risk of NOT riding a bike?

*Obviously, the life-extending benefits of exercise have limits, otherwise we could all live forever just by exercising enough to extend our lives by at least 24 hours each day. If you dig deeper into the linked articles and studies, you’ll find that the limit is somewhere in the 1-2 hours per day range, depending on exercise intensity (cycling is pretty low intensity, so let’s say two hours to max out the benefits).

I don’t know about you, but even as a retired person with a bike, I still don’t always get 2 hours of exercise every day. For the average modern citizen, the stats tell us that the average level is far, far lower – many people get ZERO exercise beyond walking between the car, office, fridge, and couch. Maybe a visit to the gym or yoga a few times a week. For the average person, getting up to an hour a day will deliver spectacular benefits, and when you rule out “car clown” behavior (using a car for any trips less than 2-3 miles), it happens automatically.

Your situation might be different, but remember the intent of this blog is to change the behavior of a big swath of smarter-than-average people stuck in average situations. So I stand by the general accuracy of this part of the argument.

Further Reading: a random collection of bike stats at bikesbelong.org: http://www.bikesbelong.org/resources/stats-and-research/statistics/safety-statistics/

A nice comparison of safety stats at the Ohio Bicycle Federation that reinforces how damned safe bicycling is: http://ohiobike.org/images/pdfs/CyclingIsSafeTLK.pdf

Today’s Dilbert is appropriate for this: http://www.dilbert.com/2013-06-14/

An amazing story of the effects of bike transportation in other countries at The Guardian.