Single-rider crashes are more common than you’d expect

by Matt de Neef


A question for you: what’s most likely to cause you to crash while riding on the road? Chances are you’re most afraid of being hit by a car, or riding into a car that’s pulled in front of you without looking, or riding into a door someone’s flung open into your path.

In short, it’s cars that pose the greatest risk to road cyclists, or that seem to pose the greatest risk. It’s no coincidence that the bulk of cyclist safety research is dedicated to understanding how multi-vehicle crashes occur.

But new research out of Melbourne’s Monash University suggests that single-rider crashes might be more common than you’d think. That is, crashes that don’t directly involve another vehicle. According to the paper, published this month in the journal Injury Prevention, single-bicycle crashes are an “under-recognised contributor to cycling injury”. They’re underreported in police data, and they’re on the rise in Australia and the Netherlands.

In the Monash study, researchers interviewed patients in Melbourne’s two biggest trauma hospitals — the Royal Melbourne Hospital and the Alfred Hospital — to better understand how cyclist crashes occur and the impact they have on the riders involved. It’s a study that builds on previous Monash research, published in the Medical Journal of Australia in 2017.

While other research has looked at single-bicycle crashes in the past, the authors of the Monash paper suggest that the interviewing of patients makes their research “the first in-depth study of cyclist crashes specifically able to examine single-bicycle crashes”.

“There are a few studies that have looked at this previously but these studies commonly use routinely collected data and often that’s fairly limited in terms of the insight you can get into the causes and characteristics of these crashes,” said Dr Ben Beck, the paper’s lead author. “And this is where the real benefit comes from sitting down and actually interviewing someone in hospital to get the specifics of exactly how these crashes actually occurred.”

What they found

Dr Beck and co found that 48% of crashes they investigated were single-bicycle crashes — probably a higher proportion than you might expect.

“We’ve had a look at these data more broadly and single-bicycle crashes are actually quite a big problem and it’s a growing problem,” he told CyclingTips. “What we know in Victoria is that these types of crashes are on the rise and represent approximately half of all serious injury crashes.

“The challenge here is that, given the lack of robust exposure data or participation rates, what we’re not sure about is how much of the increasing crash rates are simply explained by more cyclists on the road. But nonetheless these single-bicycle crashes are really under-recognised as a significant contributor to injury.”

In their Injury Prevention paper, Dr Beck and his colleagues broke down the study’s single-bicycle crashes into categories, to understand the most common factors involved in such crashes. They found the following:

37% were due to “loss-of-control events”. This could involve sudden braking to avoid another road user, losing control on a descent, or losing control in wet/slippery conditions.

19% were the result of an “interaction with tram tracks”. This normally occurred when a rider turned right across tram tracks, or when trying to avoid parked (or parking) cars.

13% resulted from hitting a pothole or other object on the road.

10% came from mechanical issues, such as wheel failures, snapped chains and gearing issues.

21% came from “other events”. These included run-ins with animals (one crash each involving a kangaroo, wallaby and a magpie) and crashes during racing (two instances).

By definition, single-bicycle crashes don’t directly involve other vehicles, but Dr Beck and co found that the influence of fellow road users was never too far away.

“We know that 42% of single-bicycle crashes involved a motor vehicle in some way,” Dr Beck explained. “So while the cyclist may not have been struck by the motor vehicle or struck the motor vehicle, the motor vehicle may have contributed to the crash in some way.

“An example of this is a cyclist avoiding an opening car door or having to swerve to avoid another motor vehicle. We did see that in quite a few situations, such as where the cyclist had to perform a sudden braking maneuver to avoid a motor vehicle or another cyclist.”

Anatomy of a crash victim

In chatting with those involved in single-bicycle crashes, Dr Beck and his team were able to paint a picture of the average crash victim. Some elements of that portrait are just as you might expect; others are more surprising.

“Single-bicycle crashes commonly involved males, cyclists with more than 10 years of experience and cyclists who rode more than three times per week,” they write in their Injury Prevention paper. “Most crashes occurred during daylight hours in clear weather conditions.”

It’s perhaps unintuitive that most crashes would involved experienced riders. It’s certainly a finding that caught Dr Beck off guard.

“I expected these crashes to be occurring in relatively inexperienced riders and quite to the contrary we saw that this was mostly occurring in very experienced riders,” he said. “I think it’s potentially an artifact of the fact that people who ride more are more exposed to crashing.”

When it came to the outcome of crashes, Dr Beck and co found that riders involved in single-bicycle crashes tended to be less severely injured than those involved in multiple-vehicle crashes. That’s not too surprising — crashing on your own is generally likely to be less damaging that being hit by (or riding into) a car. Interestingly though, the researchers found that riders involved in single-bicycle crashes tended to end up spending a similar length of time in hospital compared with those involved in multi-vehicle incidents.

But riders involved in single-bicycle crashes tended to make more complete recoveries — a little over half of such riders (53%) were back doing everything they could pre-crash when surveyed a year later. The same was true for only a quarter (26%) of those involved in multi-vehicle crashes.

The challenges

There were a few challenges Dr Beck and his team came across in the course of this research. For starters, only those who could be interviewed (and who could consent to the interview) were able to take part. This ruled out the most seriously injured of riders, such as those with significant head injuries.

And then there’s the issue of sample size. In all, the researchers interviewed a total of 129 patients with cycling-related injuries. With just 62 of those being involved in single-bicycle crashes, the researchers didn’t exactly have a massive sample size to work with. It’s a limitation they acknowledge in their paper: “The in-depth crash investigation techniques used in this study to determine crash characteristics are not possible at a population-level,” they write, “and hence the sample may not be representative of the wider population.”

As Dr Beck notes, we need to be careful extrapolating too much from this one study — the trends found in one small subsection of the cycling population don’t necessarily translate to that population as a whole.

“These results really apply to metropolitan Melbourne,’ Dr Beck said, “and there is going to be some differences when we look at regional crashes.”

That’s not to say the study is useless; far from it.

“I think the advantage of these studies is the ability to get to a fine level of detail and you can’t do that at a population-level,” Dr Beck explained. “You are reliant on, for example, police-reported crash data. So in this case the strengths are that we really get in depth with these crashes and start to really unpack exactly how they’re happening.”

What we can take from this

Dr Beck and his colleagues believe there are a few takeaways from their study; takeaways that can be applied to help reduce the risks cyclists face. They point to the obvious ones, like more regular road maintenance for cyclist-popular routes, to prevent the risk of hitting potholes or other hazards. And then there’s a more significant recommendation.

“We saw a number of cases where cyclists had to maneuver around a parking or parked vehicle and in doing so had to cross the tram tracks and therefore, and commonly, had wheels get stuck in the tram tracks and they crashed following that,” Dr Beck said.

“One opportunity to reduce these crash types is to remove parking on streets where tram tracks are present and in locations where we know that cycling is promoted.”

Dr Beck points to the likes of Sydney Road in Melbourne’s north and Chapel Street in the south as examples of roads where tram routes coincide with high cycling volume. While removing parking in such areas sounds good in theory, the presence of local traders on both strips makes the prospect a challenging one.

In closing

This latest study from Dr Beck and his team provides a greater understanding of how road cycling crashes occur. Sure, the information is gathered from just two hospitals in one city, and the sample size is limited, but it’s still useful info for those who are working to help prevent such crashes.

As for us cyclists, this research provides a few timely reminders. Ride defensively, expect that drivers haven’t seen you, and if you’re in Melbourne, be particularly mindful when riding around tram tracks. Oh, and keep your bike in good running order. While many crashes are beyond our control, some certainly aren’t.

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