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Why are modern cars so big and heavy?

Cars are so big and heavy these days!

Yes, yes they are. But the popular narrative about it all being consumer-driven, a suggestion made usually with associated snark, isn’t quite right. Regulations also have their part to play, and none more so than safety.

Today’s cars have crush cells where the occupants sit in a very strong shell that is highly resistant to damage. Take a look at an old car multiple-rolling; you’ll see the roof caves in and the A, B, C pillars simply snap or crush. A modern car is strong enough to roll and not be so deformed, protecting its occupants. Just look at the thickness of the pillars on a new vs old car, and by the way that introduces a visbility problem but that’s an aside.

This cell of course is strong and heavy, so there’s some weight. It is also large. In a modern car you sit much further from the doors than you do in an older one, so for a given amount of room in new car you need more exterior space than in an old one. Then consider the thickness of the doors. No more flimsy sheets of metal with a handle, now doors are thick devices with side protection bars. Then there are airbags. They take up space too in pillars, dashboards and various other places. If you want to preserve interior space, then the exterior must become larger. Pedestrian safety also means carefully designed bonnets and frontal areas which can add both weight and size too.

Then we come to the engine. Remember the days of lifting a bonnet and seeing an engine somewhere in the bay, and you could see the ground under the engine? No longer. So many electronic aids for safety, and emissions controls, all of which take up space and add weight.

All of these safety and emissions features add weight, and size. And that’s a vicious circle, as weight begets weight. For example, a 1500kg car needs heavier-duty wheels, tyres and chassis than a 1000kg car, and the strong components weigh more, hence the vicious circle of weight.

Finally, we come to consumer choice, and that’s where aircon, electric seats, power windows, mirrors, power this that and other comes in. Every electric motor adds a little weight and bulk, as does soundproofing. This is the one area where it might be said consumer choice plays a part, but who really wants to do without aircon or power windows?

The modern car is in fact a marvel of engineering and the fact is it vastly safer, easier to use and more fuel-efficient than older cars is a credit to the industry. Consider though how fuel efficient a car could be made if safety, convivence and NVH were not a concern – maybe a ’60s Fiat 500 with a modern engine, transmission and tyres? Fantastic on fuel, but you wouldn’t want to crash it. Or conversely, take a ’60s engine and put it in a modern car, see how good the fuel efficiency is then.

This “cars are fat and big because of consumer demand” narrative misses the bigger picture.

And while I’m at it, the modern SUV is essentially just a roadcar, most are 2WD. You give up nothing in terms of safety, handling etc and gain useful ride height. I don’t get the hate for small runabout SUVs – it’s not like back in the day someone chose to drive a 60 Series instead of a Corolla, and even then, who gets to judge other people’s choices without even knowing the circumstances?

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