You might think that designing a new car is easy, but once you factor in the different shapes and sizes of the occupants, things get a whole lot more complicated. We test a wide range of different vehicles using a pair of models at the opposite end of the size spectrum. Sue Baker reports.
At just five feet tall, or slightly over one and a half metres, Hannah Downing is towards the shorter end of the female spectrum. She is what ergonomists term “eighth percentile”, meaning that only eight per cent of the population are shorter than she is. At the other end of the scale, Max Pritchett, at six feet seven inches tall, is exactly two metres from top to toe, and deemed to be “99th percentile”, right at the top of the chart for height.
These two young people are at the outer limits of what motor manufacturers plan for when designing car cabins, deciding instrument layouts and setting seat adjustments. Not to mention sculpting rooflines, setting pedal heights, planning the layout of controls, setting the level of seatbelt delivery and deciding sun visor depth. So much of the way a car interior is designed has to take size differences into account. This human height variation in relation to cars is increasingly relevant. Young people are – mostly – growing taller, so car manufacturers increasingly have to factor in a greater elasticity to accommodate larger people. But at the other end of the scale, we are an ageing population, and people tend to shrink as they get older. This is one element that influences why cars are becoming taller: the raised ‘hip point’ at which people sit in vehicles, and just as importantly the level at which they swing into them to sit down, benefits older drivers with declining agility. Incidentally, we all shrink as the day progresses. Measure yourself at teatime, and you will find you are about half an inch shorter than you were at breakfast time. Odd, but true.
In the car world, it helps to be average, somewhere between the modest 5 ft 3 inches of a typical female (below that, you’re deemed to be ‘petite’) and the fairly standard 5 ft 10 or thereabouts of a typical man. Life at the outer edges can be annoying. Many are the six-footer colleagues who complain of insufficient headroom in some cars, and of the short squab length of the seats in others. Just as irksomely, anyone who is – as the saying goes – “vertically challenged” will often find themselves shunting the driving seat between too-far pedals and too-close steering wheel, and also stretching to reach barely accessible switches at the outer limits of convenient touch on the dashboard.
To find out what the driving experience is like at the outer extremities of the size scale, and how well different cars cope, we decided to put on test a range of models – that vary hugely in size – with our short and tall drivers assessing them for comfort and convenience. It is interesting to see what our two guinea-pig drivers choose to drive as their own cars. Hannah, 25, has a BMW 118d, in which she feels very much at home. Max, 22, has a Vauxhall Corsa, the same model as the one in which he learned to drive. Odd, surely, that the smaller driver owns the larger car? No, that is just a matter of age, driving experience and economics.
Our assessment started with Britain’s best-selling car, the Ford Fiesta. For our small driver it is an excellent fit, good for accessibility and driving position, with no particular issues. Lofty Max was dubious, though. “I don’t fit well in a Fiesta,” he declared. “It is not designed for someone my size.” Then came a surprise. He hadn’t been in the current model until now, and he fitted in alright. “I’ve tried them before and they were rubbish for someone my size, but this latest one is better. Yes, I’m ok with this.”
Not so the Fiat 500. Cute and curvy, it is unsurprisingly popular with female drivers. It fitted Hannah fine, but was a no-no for Max. “Too small for me. My head is wedged against the roof. It’s a joke”. In that case our next car, a Peugeot RCZ, would be a problem too, we thought. Not at all. Both our height-extreme drivers fitted snugly and loved it. “There is plenty of adjustment, so it’s fine for me,” said Hannah. “This is great, the seat goes a long way back and although the roof looks low and swoopy there’s enough room for my height,” said Max. A Mercedes-Benz A-Class passed muster too. The baby Benz, with its good range of seat settings, steering wheel adjustment and seat belt height variation, fitted fine for both our guinea-pigs, although Max found it quite tight for headroom.
Now came the acid test: we lined up one of the smallest cars on the market and one of the largest: a dinky little Renault Twizy and a huge Audi Q7. How would our opposing pair fit into these? The result was a revelation. The little Twizy looked perfectly scaled for Hannah, but it was a thumbs-down from her. “It’s so small, you feel intimidated in it on the road,” she complained. Even more surprising was seeing Max install himself into it. “Look at the headroom, I’ve got loads,” he enthused, even though he had to have the driving seat set so far back that there was negligible room for anyone else in the tandem passenger seat behind him. The Q7 was more of a hit, oddly, with our small driver than our big one. “It’s brilliant, I feel really comfortable in it. There’s loads of adjustment and it makes you feel confident sitting this high up,” said Hannah. When Max tried, his very long limbs shoehorned in fine, and there was enough headroom for him, but he would have liked the seat runners to go further back.
One lesson learned from this exercise is that car companies are making a better job of accommodating extremes of driver size than they used to. They have twigged the need to provide plenty of adjustment, and to bear tall drivers in mind when planning for headroom. In the fronts of cars, anyway. Back seats are often more of a problem for very tall passengers thanks to shapely rooflines.
And over-six-footers may need to think twice before ticking too many option boxes. Forego a sunroof, and you get more space. Richard Graveling, president of the Loughborough-based Institute of Ergonomics and Human Factors, explains why: “A few years ago the trend for fitting sunroofs in UK cars caused difficulties as the roof height was sized to the 95th percentile – but then the housing for the sunroof intruded into this space reducing the effective height available. As a result, those with long bodies and a tall sitting height found that they had to adapt themselves to fit, perhaps by leaning backwards more, or simply not buying such cars.”
|LENGTH OF VEHICLE||MAXIMUM FRONT HEADROOM||HAXIMUM REAR HEADROOM|
|Fiat 500||3,546mm||not quoted||not quoted|