Do drivers give female riders more space when overtaking?

by Matt de Neef

Over two days in early 2006, British researcher Dr Ian Walker rode his bike up and down a stretch of road in the city of Salisbury, stopping every few minutes to put on or take off a long, feminine wig. He wasn’t doing it for fun — it was part of a study looking at the factors that affect how much space drivers give when overtaking cyclists.

Using an ultrasonic distance sensor mounted to his bike, Walker measured how much space drivers left when passing, when he was wearing the wig and when he wasn’t. In Walker’s own words, “On average motorists left considerably more space when passing the rider when he gave the impression of being female.” While wearing a wig, Walker was given an average of 1.37m of space by overtaking drivers. Without the wig, that average was 1.23m.

Why the extra room? Walker surmised there were a few factors.

For starters, he posed, “it could simply be a product of female cyclists being more unusual on Britain’s roads than male cyclists.” Or it “may also be a product of politeness, or a form of risk-compensation strategy based on women being seen as more frail.” Finally he questioned whether “motorists in general feel female bicyclists are less predictable than male riders and thus leave more space when passing.”

Before you go putting on a blond ponytail wig for your work commute, it’s important to take a look at the bigger picture and put things into context. Walker’s finding came from one study of one street in one city in one country, more than a decade ago. To say that the finding holds true across all jurisdictions would be a significant stretch.

Thankfully, in the years since Walker’s study, there’s been plenty of further research looking at the factors that affect the distance drivers give when overtaking cyclists. Many of these studies have been prompted by the introduction of minimum distance passing laws (MDPLs), including in Australia where nearly all states and territories now have a MDPL of some kind.

Among the recent research is a June 2018 paper published in the Journal of Transport & Health, looking at the Australian context. So what can this study tell us about the effects of gender on overtaking distance? Do Australian drivers give more space when overtaking female riders? If so, why? And are there other factors that affect how much room cyclists are given, besides their apparent gender?

In 2006, Dr Ian Walker found that he was given more space by passing drivers when wearing a ponytail wig.

The Queensland experience

In April 2016, the Australian state of Queensland implemented a MDPL after a successful two-year trial. Under that legislation, drivers must give cyclists 1m of space when overtaking on roads with speed limits of 60km/h or less, and 1.5m for faster roads. To assist in this, drivers can cross double lines when overtaking cyclists. Any driver found not giving the necessary space can be fined $391.

When the Queensland government rolled out its MDPL legislation, it asked for submissions from those who were keen to evaluate conditions under the new law. A research group at Queensland University of Technology (QUT) were among those that responded. The Journal of Transport & Health article is among the papers to come from that research.

The QUT team set up cameras in 15 locations around Queensland — mostly in the south of the state — and recorded overtaking incidents without cyclists or drivers being aware that they were being filmed. The team analysed all the footage to see which factors affected how much space drivers gave. They considered the apparent age of the cyclists, their apparent gender, whether they were wearing a helmet, what type of clothing they were wearing (lycra or everyday clothing), the type of bike they were riding (road bike, mountain bike, or folding bike) and whether they were riding by themselves or in a group.

The researchers found that, in the context of the sites they investigated, none of those factors appeared to have a significant association with how much space drivers gave cyclists. A lack of correlation with apparent gender puts the QUT finding at odds with Walker’s 2006 research. It also clashes with Taiwanese research from 2013 that found that drivers give roughly 10% more space to female riders. It would seem that it’s not as easy as saying “female cyclists get more room from overtaking drivers”.

And there are other factors affecting overtaking distance that are hard to pin down with great certainty.


In 2014, in a follow-up to his 2006 study, Dr Ian Walker found that the type of clothing a rider wore had little impact on how much space drivers gave them. “Contrary to predictions, drivers treated the sports outfit and the ‘novice cyclist’ outfit equivalently,” he wrote at the time, “suggesting they do not adjust overtaking proximity as a function of a rider’s perceived experience.”

The clothing arrangements that Walker tested for his 2014 paper. Only the jacket led to drivers allowing more room.

Researcher Amy Schramm and her QUT colleagues found something similar when they looked at 10 of the 15 sites they collected footage from (the sites that provided a not-insignificant number of overtaking manoeuvres) — that clothing choice made no difference to overtaking distance. Interestingly though, when Schramm and colleagues looked at a different subset of Queensland sites (four of the initial 15, “where at least 10 female riders were observed being overtaken per data collection day”) they found that drivers did provide more room to riders who were wearing street clothes than those wearing lycra.

Why? The researchers noted that clothing choice was strongly correlated with bike choice — those who wore lycra were likely to be on road bikes. And as Schramm wrote in her paper: “Drivers might consider riders of road bikes to be more experienced and therefore to have a more predictable trajectory, and so leave a smaller distance when overtaking.”

So what are we to make all of this? Different studies seem to show both that gender does and doesn’t affect overtaking distance, likewise with clothing choice (in the same state, no less). So do gender or clothing choice matter or not?

Data clash

As is so often the case in the world of research, the answer is far less definitive than we’d all like. Certainly far less definitive than we’d need to say “yes, women get more overtaking room” or “wear street clothes to be given more space”. In this case it would appear there’s no single answer or absolute rule, nor even an appropriate generalisation that can be made. Context is king.

When asked about the inconclusivity of the research, Schramm points to a study out of Spain — a study that helps to show how much things differ from country to country, let alone state to state.

“Around 90 something percent of all passes were compliant,” she said of a study that looked at overtaking manoeuvres on rural Spanish roads. “90% of drivers were giving cyclists more than 1.5 metres when they overtook. Whereas if you look at data we found in Australia, or in Queensland particularly, it found that higher speed roads — so generally then the more rural roads — you get actually less compliant passing in Australia than you do in lower speed zones.

“So I think road culture and study methods interact.”

The QUT researchers used footage from roadside cameras to classify overtaking events. Image: Journal of Transport Health.

Overtaking distances seem to depend on a lot of factors, even within one state. That’s certainly what Schramm and co found in Queensland.

“We have to remember that all the 15 sites [in Queensland] vary significantly in terms of who was riding and where they were riding and then what the road environments look like,” she said.

Different parts of the state mean different demographics, different infrastructure, different speed limits, different attitudes towards cyclists and maybe even different rider abilities. With so many variables, it’s nigh on impossible to get a definitive answer.

“In an ideal world what you would do is you would have 20 observation sites with exactly the same road configuration with the exact same proportion of people riding the same traffic volume, the same number of traffic lanes, the same road curvature, the same vertical incline or lack of incline depending on what your perspective is,” Schramm said. “And then you would look at those sites and then you would be able to see whether it was the road environment or rider environment [that affected overtaking distance] or a combination of everything.”

If that sounds highly unrealistic, not to mention a whole lot of work, you’d be right.

“It’s really hard in a real-world environment to get that kind of clear demarcation and only changing one thing per observation group to be able to make that kind of clear categorical statement that ‘it’s definitely this one thing that makes the difference’.”

And besides, even if an environment could be constructed to test in the way that Schramm outlines, doing so would lose one of the biggest benefits of the QUT studies — the fact they observe people in their native habitat rather than in a sterile environment where they know they’re being assessed.

Humans tend to change their behaviour when they know they’re being watched. That makes it hard to study human behaviour as objectively as we’d like. Image: Tejvan Pettinger

“As soon as people are aware that they’re being looked at, their behaviour will change and how their behaviour changes can vary depending on each person,” Schramm explains. “Some people tend to be more aggressive [when overtaking] to prove a point, other people will be more conservative to show that they’re a really good driver and the reasons why they choose to display a certain attribute is complex as well.

“People are the problem in a lot of systems and they make studying people incredibly difficult.”

In summary

So where does that leave us? In essence there are no clear answers — overtaking distance seems to depend on a patchwork of intersecting factors. Schramm and co suggest in their Journal of Transport & Health paper that vehicle type, traffic volume, and speed limits have the most notable impact on overtaking distance, at least in the sites they studied.

But as with rider gender and clothing type, the affect of these factors appears to be region-specific. It would seem there are no hard-and-fast rules that hold true across jurisdictions, or even within.

So is there anything we can take from this? Anything that we riders can do ensure we’re given as much room as possible?

“Well, it’s complicated,” Schramm says. “Potentially [riders need] to be aware of situations where drivers either perceive difficulty or it is difficult [to overtake].”

Often that difficulty will be as a result of narrow roads or infrastructure that makes things complicated for drivers and cyclists to coexist.

“Motorists were more likely to be non-compliant [of passing distance laws] at horizontal road curves, perhaps due to motorists’ poorer lane-keeping behaviour at curves,” Schramm and colleagues write in a paper for the Accident Analysis & Prevention journal. “A large body of research … showed that vehicle position within traffic lanes varies at horizontal curves, and often drivers do not drive in a circular path when negotiating a horizontal curve.”

Image: Kristoffer Trolle/Flickr

For Schramm, a lot of it comes down to a need for everyone to take responsibility for their actions on the road.

“Part of that is asking drivers to be a little bit more aware of what they have to do and their responsibilities and the fact that there are riders on the road,” she said. “And the other bit is cyclists being aware that sometimes drivers might not get to practice that skill very often.

“And it’s a big burden to ask of cyclists because they’re already trying to power their vehicle and control their vehicle at the same time which is a little bit more than what you’re asking drivers to do …”

Ultimately, more research is required to fully understand why drivers do or don’t give sufficient distance when overtaking cyclists, and what factors can affect that distance. And as ever, appropriate infrastructure for cyclists is all-important.

“The findings of this study suggest that rider characteristics have limited to no effects on the passing distance compliance levels,” the paper reads. “Therefore, the focus for improving cyclist safety during overtaking events should be on non-rider related factors, such as roadway infrastructure characteristics.”

So if you want more room when drivers overtake, your best bet might be to continue lobbying the powers that be to continue spending on safety infrastructure. Which, sadly, isn’t nearly as simple as donning a blond ponytail wig or swapping your lycra for street clothes.

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