A considerable gender data gap remains. We don’t yet know exactly how and when women’s body-sway changes. But as a woman who suffers from extreme car sickness, I am excited and enraged by Stoffregen’s findings, particularly because of how it ties into another gender data gap I’ve been looking into: car design.
When you’re sitting down, you’re still swaying. ‘If you’re sitting on a stool then you’re swaying around your hips,’ explains Stofcegen. ‘If your chair has a back, then your head is swaying on your neck. The only way to really get rid of that is to have a headrest and to use it,’ he adds. And I feel like one of those cartoon light bulbs has just gone off in my head. What if the headrest is at the wrong height, at the wrong angle, and the wrong shape to accommodate your body? Could women’s increased propensity to motion sickness in cars be exacerbated by cars being designed around the male body, I ask. ‘I think that’s quite possible, sure,’ Stoffregen replies. ‘The quality of the stabilisation, if it’s the wrong height or whatever . . . what you’re telling me is new to me, but it sounds perfectly plausible.’
But here I run into yet another data gap: the available research on whether car headrests have been designed to account for the female body is seemingly non-existent. This gap is hardly unexpected though: car design has a long and ignominious history of ignoring women.
Men are more likely than women to be involved in a car crash, which means they dominate the numbers of those seriously injured in car accidents. But when a woman is involved in a car crash, she is 47% more likely to be seriously injured than a man, and 71% more likely to be moderately injured,46 even when researchers control for factors such as height, weight, seat-belt usage, and crash intensity.47 She is also 17% more likely to die.48 And it’s all to do with how the car is designed – and for whom.
Women tend to sit further forward than men when driving. This is because we are on average shorter. Our legs need to be closer to reach the pedals, and we need to sit more upright to see clearly over the dashboard.49 This is not, however, the ‘standard seating position’. Women are ‘out of position’ drivers.50 And our wilful deviation from the norm means that we are at greater risk of internal injury on frontal collisions.51 The angle of our knees and hips as our shorter legs reach for the pedals also makes our legs more vulnerable.52 Essentially, we’re doing it all wrong.
Women are also at higher risk in rear-end collisions. Women have less muscle on our necks and upper torso than men, which make us more vulnerable to whiplash (by up to three times53), and car design has amplified this vulnerability. Swedish research has shown that modern seats are too firm to protect women against whiplash injuries: the seats throw women forward faster than men because the back of the seat doesn’t give way for women’s on average lighter bodies.54 The reason this has been allowed to happen is very simple: cars have been designed using car-crash test dummies based on the ‘average’ male.
Crash-test dummies were first introduced in the 1950s, and for decades they were based around the fiftieth percentile male. The most commonly used dummy is 1.77 cm tall and weighs 76 kg (significantly taller and heavier than an average woman), and the dummy also has male muscle-mass proportions and a male spinal column. In the early 1980s, researchers argued for the inclusion of a fiftieth percentile female in regulatory tests, but this advice was ignored.55 It wasn’t until 2011 that the US started using a female crash-test dummy,56 although, as we’ll see, just how ‘female’ these dummies are is questionable.
In 2018, Astrid Linder, research director of traffic safety at the Swedish National Road and Transport Research Institute, presented a paper at the Road Safety on Five Continents Conference in South Korea in which she ran through EU regulatory crash-test requirements.57 In the EU, there are five tests a car must pass before being allowed on the market: one safety-belt test, two frontal-collision tests, and two lateral-collision tests. In no test is an anthropometrically correct female crash-test dummy required. The seat-belt test, one of the frontal-collision tests, and both lateral-collision tests all specify that a fiftieth-percentile male dummy should be used. When Linder looked at regulatory tests worldwide, she found that while there are ‘several local differences’, regulatory tests are still using the fiftieth-percentile male ‘to represent the whole adult population’.
There is one EU regulatory test that requires what is called a fifth-percentile female dummy, which is meant to represent the female population. Only 5% of women will be shorter than this dummy. But there are a number of data gaps. For a start, this dummy is only tested in the passenger seat, so we have no data at all for how a female driver would be affected – something of an issue you would think, given women’s ‘out of position’ driving position. And secondly, this female dummy is not really female. It is just a scaled-down male dummy.
Consumer tests can be slightly more stringent. When I spoke to the EuroNCAP (a European organisation that provides car safety ratings for consumers) they informed me that since 2015 they have used male and female dummies in both front-crash tests and that they do base their female dummies on female anthropometric data – with the caveat that this is ‘where data is available’. And that, says Linder, is quite the caveat: ‘To my knowledge, little or even no such data is available,’ she tells me, adding that there is ‘currently no way EuroNCAP can identify the protective systems that protect both males and females the best way.’ In any case, EuroNCAP acknowledged that ‘sometimes’ they do just use scaled-down male dummies. But, as we’ll cover extensively in the next chapter, women are not scaled-down men. We have different muscle-mass distribution. We have lower bone density. There are sex differences in vertebrae spacing. As Stoffregen has noted, even our body sway is different. And these differences are all crucial when it comes to injury rates in car crashes.