Do our perceptions about the relative safety of bicycling, driving, motorcycling, transit, and walking match the available data?
In North America, concerns about safety consistently rank as the top deterrents to bicycling. Most of us don’t like the idea of riding in traffic next to heavier vehicles that are traveling at higher speeds. Our perceptions about these routes are right – on busy streets, Dutch and Danish-style protected bike lanes are safer than riding in mixed traffic. And in places with abundant separated lanes, cycling is much more common.
Given that safety concerns affect our choice of travel mode, I often wonder about these perceptions about the relative safety of bicycling, driving, motorcycling, transit, and walking. Do our perceptions about these modes match the data?
Comparing is not easy. It is common to simply report numbers. For example, in 2012 in the US, 726 cyclists were killed in traffic crashes.1 But 22,912 motor vehicle occupants (including 39 bus occupants) were also killed, as were 4,957 motorcyclists and 4,743 pedestrians.1 Traffic deaths in 2011 in Canada (with about one-ninth the US population) included 51 cyclists, 1,420 vehicle occupants, 168 motorcyclists, and 315 pedestrians.2
Of course, numbers don’t indicate risk. Risk requires a denominator – one that reflects “exposure.” How many people use these modes to travel? How often, how long, how far? The most common ways to compare transport risks are per trip or per distance traveled. Per trip is a great way to compare if your travel mode influences how far you go. For instance, if you go shopping by bike or on foot, you may choose to go to a neighborhood store rather than a mall far away. Comparisons by trip are analogous to comparisons by time traveled. Per distance traveled might be more appropriate if you have less control of the trip distance, for example, a commute.
The other part of risk is the numerator. Should we consider deaths, serious injuries, or all injuries? There are reasons to suggest that deaths are the best choice. Deaths are the most serious and concerning outcome. Data quality is another reason. Traffic deaths are systematically recorded in most countries and are most complete for all travel modes, maximizing our ability to compare. Injuries are not consistently reported for walking and bicycling. Hospital data makes it difficult to distinguish sport cycling, like mountain biking, from transportation cycling. Walking hospitalizations are often miscoded as falls.
With this in mind, what does published data show? An especially helpful study was done early on by the US Centers for Disease Control and Prevention.3 It compared deaths per trip for 5 travel modes (shown in the first graph). We replicated it, in part, in British Columbia (BC), Canada.4 The data shows such dramatic differences between travel modes that they are plotted on a log scale. Motorcycling, the most dangerous mode, has more than 1000 times the death rate of the safest mode, bus travel. In comparison, bicycling is similar in safety to driving and walking. If you want to maximize safety, transit is definitely the right choice.
Broader international comparisons are available using distance denominators (shown in the second graph). A caution: except the Canadian (BC) data,4 the driving data is from a different and more recent source5 than the walking and bicycling data;6 how well they compare is unknown. Even so, the picture is the same, the longer distances traveled make driving look safer in every country. Bicycling looks safer than walking for the same reason.
This graph also shows what bicyclists have long known, cycling is much safer in the Netherlands. Perhaps less well known is that walking and driving are much safer there too. The overall traffic death rates (across all modes) are 10.4/100,000 people in the US and 6.5/100,000 in Canada, vs. 4.0/100,000 in the Netherlands.5 Other European countries have similarly low death rates: Sweden, Norway, Denmark, the UK.5 Prioritizing traffic safety makes a remarkable difference. Achieving these low rates in the US and Canada would save ~ 20,000 lives a year.5,7
I wonder whether this data makes you feel more or less worried about cycling? Personally, they make me feel more comfortable. Even in North America, walking feels safe to me, so cycling should too. Another way to look at the data is this: in the US, there was one cycling death per 4.8 million trips or per 18 million km traveled. And of course, cycling (like walking) has health benefits because of the physical activity involved: reductions in heart disease, diabetes, stroke, dementia, certain cancers.8 A number of studies have compared lives saved via these health benefits to lives lost via injuries. In every comparison so far, in the US, the UK, Spain, and the Netherlands, the benefits far outweigh the risks – by at least 9 to 1 (some estimates are as high as 96 to 1).8
The data also shows the huge potential for gains in safety. For cycling, a new approach is beginning to take hold: protected bike lanes, narrower car travel lanes, and lower speeds. Evidence is emerging that these changes reduce injuries not only to people on bikes, but to those walking and driving too. Wonderful news for the safety of all modes.
What about cycling for sport?
Bicycling is also often compared to sports, but injury numbers, not rates, are reported. This graph presents a rare comparison of injury rates across a wide range of sports.9 The data are not ideal (numerator = self-reported injuries requiring medical treatment, not deaths; denominator = participants, not frequency or time spent), but the survey – done in Quebec, Canada – included 8,500 households and the method produced comparable data across all sports.
While we understand that some journeys simply cannot be made by bicycle, after reading the following guide you’ll discover just how many opportunities there are to hop on your bike.
1. National Highway Traffic Safety Administration. Traffic Safety Facts 2012 Data Overview. 2014. http://www-nrd.nhtsa.dot.gov/Pubs/812016.pdf
2. Transport Canada. Canadian Motor Vehicle Traffic Collision Statistics 2011. 2013. http://www.tc.gc.ca/media/documents/roadsafety/TrafficCollisionStatisitcs_2011.pdf
3. Beck LF, Dellinger AM, O’Neil ME. Motor vehicle crash injury rates by mode of travel, United States: using exposure-based methods to quantify differences. American Journal of Epidemiology. 2007;166(2):212–218 http://aje.oxfordjournals.org/content/166/2/212.full.pdf+html
4. Teschke K, Harris MA, Reynolds CCO, Shen H, Cripton PA, Winters M. Exposure-based traffic crash injury rates by mode of travel in British Columbia. Canadian Journal of Public Health. 2013;104(1):e75–79 http://journal.cpha.ca/index.php/cjph/article/viewFile/3621/2744
5. International Transport Forum. Road Safety Annual Report 2013. http://www.internationaltransportforum.org/pub/pdf/13IrtadReport.pdf
6. Buehler R, Pucher J. Walking and Cycling in Western Europe and the United States. Transportation Research News. 2012:280(May-June):34-42 http://policy.rutgers.edu/faculty/pucher/TRNWesternEurope.pdf
7. Evans L. Twenty thousand more Americans killed annually because US traffic-safety policy rejects science. American Journal of Public Health. 2014;104:1349-1351 http://ajph.aphapublications.org/doi/abs/10.2105/AJPH.2014.301919
8. Teschke K, Reynolds CCO, Ries FJ, Gouge B, Winters M. Bicycling: Health risk or benefit? UBC Medical Journal. 2012;3(2):6-11 http://www.ubcmj.com/pdf/ubcmj_3_2_2012_6-11.pdf
9. Hamel D, Tremblay B. Etude des blessures subies au cours de la pratique d’activités récréatives et sportives au Québec en 2009-2010. Institut national de santé publique du Québec, 2012. http://rseq.ca/media/844914/etudeblessuresrecreasportqc2009-2010.pdf
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Great article Kay. Where I am (London) there’s also the issue of other modes of transport being very unsafe.
We’re currently losing 9500 people a year to air pollution, with half of those deaths caused by the pollution from motor vehicles. ( see independent.co.uk/news/uk/home-news/nearly-9500-people-die-early-in-a-single-year-in-london-as-a-result-of-air-pollution-study-finds-10390729.html )
London is a green city with many parks, so if this is happening here then I dread to think what the effects of driving are in other more condensed cities.
So people may feel safer inside their cars rather than on a bike, but in reality they are decreasing the safety for all of us.
Anyway, keep up the good work
Hi Kay, dropping by to tell you that I loved your post. I believe that riding a bike is the best transport ever. I can`t get off of my bike when the weather is nice outside.
Thanks, Momentum Magazine for publishing this article!
The log bar graphs look comforting but at 21 fatalities vs 14 for walking (over 50% higher) and 9 for driving (more than double), the graph distorts the statistics IMHO
I agree Carl. I was going to say as much. For me, this article fails by giving a hand wave to the data.
True, 21 vs 9 deaths per 100 million trips is 2x the risk. But both of these rates are almost incomprehensibly low. At 21 deaths/100m trips, a single bicyclist can ride twice a day for 6,523 years before getting killed. Now, medical science keeps improving, but you probably won’t live to see your six thousandth birthday, so your energy might be better spent worrying about something like cancer or Alzheimers.
What’s much more meaningful than “ridiculously unlikely” vs “really ridiculously unlikely” comparisons of all-comers statistics is the affect of behavior on these probabilities. This infographic tells us that there’s one bike fatality for every 4.8m bike trips. But is the risk equal for everybody? An auto insurance company would probably tell you that a 17-year old dude who drives a Mustang and has gotten 3 speeding tickets this year is more likely to die in a car crash than a middle-age mom who’s never gotten a ticket in her life. How much more likely? I don’t know but I’d bet it’s far, far more than 2x. What I do know are some bike statistics. This article gives us the rate for all bicyclists in the US: 1 death/4.8 million trips. But we also know the rate for a subset of that population: bicycle share users. There are 36 municipal bike share systems in the US, and they track trips and injuries/fatalities. Trips to-date for all these systems is over 25 million. And the fatalities count is 0. You can’t divide zero, so let’s pretend a bike-share user died today and the rate is 1 death/25 million trips. That would be 5x safer than the overall US bike rate. If it takes another two years for someone to die, it could be 10x safer than the overall rate. How could that be? All of these trips are in city centers, on terrifying streets like 6th Ave in Manhattan. And most of these riders aren’t wearing helmets. People are riding these bikes home from bars. They’re talking on their phones while riding. The rear lights on the Citibike are barely noticeable at night. And yet this group is LESS likely to die than bicyclists overall. 5x less likely, and counting.
About a year ago a bicyclist died in a park in New Jersey. It was a clear day. There were no cars in sight. She was wearing a helmet. The road surface was freshly paved. Across the river, helmetless Citibike riders were dodging garbage trucks and enraged taxi drivers and escaping without a scratch. How could the outcomes be the opposite of what you’d expect? The answer is bicyclist behavior. Specifically, speed. The bicyclist who died was descending one of the longest, steepest hills in the NYC area on a racing bike, lost control and hit a tree. Speed alone overwhelmed all the environmental factors, the protective gear, her skill level (she was an “avid” cyclist). If you want 2x or 5x (or maybe 10x) less risk, the question to ask isn’t “Car or bike?” or “Wear a crash helmet?” It’s “How should I ride?”
One of the best, most insightful comments I’ve ever read in the comments section. Ever! Thank you – this is what web 2.0 was designed for!
My thanks as well, ralph. This is something that cyclists in the English-speaking countries suffer from all the time: a widespread and apparently invincible belief among the non-cycling 97% of the population that pedalling along suburban back-streets to the public library on a 3-speed upright barely capable of 15mph on the flat is an activity just as risky as belting down winding mountain roads in the Pyrenees on a featherweight carbon-fibre racer with tyres so narrow that you can barely see them end-on. Both activities are performed on “bicycles”; ergo both require the wearing of a bicycle helmet and special bicycle clothing.
When the London hire-bike scheme started in 2010 there were widespread predictions of carnage on the streets, with hospital A & E departments overwhelmed and the dead having to be buried in mass graves. In fact in over 23 million journeys there have been two deaths and one serious injury. Why? Largely because you can’t do anything very risky on a Boris Bike…
So true Ralph. The biggest factor in the safety of bike share systems is the lack of children using it. People forget that practically all the bike crash stats in the universe include the crashes and injuries of little kids, who are far more crash- and injury-prone than their adult counterparts. Yet kids aren’t allowed to use bike share. The other big factors of course are the stability and heft of the machines, which make going fast very difficult, and the step-through frames, which make hard crashes a bit more unlikely.
Have to disagree a bit Robert. Here in NYC when you look at serious bike injury and deaths, there are actually very few children that comprise those numbers. And they certainly do bike, especially in the outerboroughs. Growing up I rode my bike all over the suburbs, as did friends of mine, and again, crashes and injuries weren’t on the radar – though I did lose a high school classmate in a car crash on an icy road in a Camaro being driven by a 17 year old boy. So there is something more going on with the relative safety of bikeshare than the exclusion of children, a presumably reckless population [though I think that is a bit unfair]. It is the bike design and the types of trips these bikes are intended for that I think is easily the biggest factor, as those affect behavior. And not just the behavior of the rider, but of drivers too, who see the municipal bikes clearly, remember the news stories about them, and for whatever reason are generally less aggressive around those bikes – something I have personally witnessed on NYC streets where I ride both my own bike and Citibikes.
None of this excellent argument changes the fact that “biking is no more dangerous” is obviously not true. It is not a coincidence that so many people have wandered down to the comments to refute those words. They’re unpersuasive. In my opinion, better to rephrase.
Ralph,
I agree in general, but you should be aware that there has been at least one fatality using bike share bikes in both Chicago and New York.
The deaths-per-trip chart is presented on a log scale. This makes it appear that cycling is almost the same risk as driving, when in fact the numbers show that it is more than twice as risky (21 vs. 9 deaths per 100 million trips). The risks only have the same order of magnitude. It’s quite interesting to note that driving, walking, and biking all have the same order of magnitude, because they produce an interesting cluster between the extremes of bus and motorcycle travel. However, a 133% increase in risk is far from “no more risky,” as it is described in the infographic. The body of the article does describe the difference as “similar,” which is reasonable language.
The log scale and associated “no more dangerous” note is detracting from a widely distributed and otherwise effective info-graphic. It feels like like a deliberate deception. There are good arguments to be made here, but this one detail is so distracting I can’t even recall what else is presented. Either the graph should be presented with a linear scale and the comment updated, or some other statistic which actually supports the safety comment should be used.
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