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. But 22,912 motor vehicle occupants (including 39 bus occupants) were also killed, as were 4,957 motorcyclists and 4,743 pedestrians. 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.
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 mis-coded 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. It compared deaths per trip for 5 travel modes. We replicated it, in part, in British Columbia (BC), Canada. 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.
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. 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).
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.