As cars get heavier, even small speed differences are important in an accident

In late January, safety investigators from the AAA Foundation for Road Safety and the Insurance Institute for Highway Safety published a study showing that small speed increases have major consequences during an accident. After three identical cars crashed at increasing speed, the study showed that a car that passes the test at 64 km / h (64 km / h) with only a 15 percent chance of serious injuries can get a pass rate with a 59 percent chance of serious injuries at 50 km / h (80 km / h). At 56 km / h (90 km / h) the result was even worse; the 50th percentile male collision test dummy has only a 21 percent chance of escaping serious injuries or worse.

The fact that vehicles are designed to pass a 45 km / h (73 km / h) crash test and not something on a highway undoubtedly has something to do with the results of the study. But it is also a reminder of basic physics: the kinetic energy of a vehicle is equal to half its mass multiplied by the square of its velocity. Thus, the average American light vehicle – which weighs about 1,814 kg – has 11.2 kJ when driving 40 km / h, but 22 km at 56 km / h, which people can use next time someone complains that city speed limits are too slow .

But speed is literally only part of the equation. Local authorities can set limits on how fast we can drive, but no one is going to stop you from buying a 2,000 kg (2,000 kg) car instead of a 4,000 pound car. And large cars are attractive to the general public. Ironically, much of this trend is fueled by the fact that safety is sold, and that the largest, heaviest cars are the safest – at least for their occupants. Pedestrians or people in older or smaller cars? Not so much.

If everything is equal, a bigger and heavier car will handle worse. You can compensate for this in some ways, such as cars over 5,000 pounds such as the Porsche Taycan Turbo, Audi RS7 and Aston Martin DBX. Quickly responsive adaptive suspension and excess power are a great way to beat inertia when it’s time to start moving or change direction. All things exist, but it all comes with its own baggage. Adjustable suspension is expensive and adds a lot of weight just on its own. Electric cars are great because they have such torque, but now you have to carry hundreds of kilograms of lithium-ion cells, which again is not cheap. And glacier-melting dual-turbo V8s are increasingly unsustainable due to the glacier-melting bit.

Powerful engines and smart dampers are good and pleasant to turn on. But you can not really hide the mass of a car when it’s time to slow down or stop. Heavy vehicles require large brakes and longer braking distances and tires that can handle all of the above, rain or shine.

Less can be more

At the other end of the spectrum is a lightweight utopia, one that designers like Gordon Murray envision. He also places his money where his mouth is; none of his personal cars – including one of the Suzuki Jimnys that everyone loves so much – weighs more than 1,134 kg if memory serves.

Lighter cars have a profit for enthusiasts as well as safety conscious. The less mass a car has to move, the better it handles. And in the first place, it will not need nearly as much power to get going. Lighter, less powerful cars have much more accessible limits, which means you can drive them nicely with socially responsible speeds. In fact, I’m still saddened by my old Ford Ka from 1996. With only 59 hp (44 kW) and 908 kg (2,002 lbs), it remains etched in my memory as one of the nicest cars to drive daily.

The true godfather of lightweight was Colin Chapman, founder of Lotus, who was perhaps more obsessed than Murray. Chapman describes his philosophy as ‘simplify, then add lightness’, and this has been a hallmark of Lotus through good and bad times. Some of the bad ones included race cars that were often too fragile for their own good, with tragic consequences. But the best were road cars that outperformed any of their competitors and often at an expensive price.

Since 1996, Lotus has existed over the success of the Elise and other lightweight sports cars, coming from the ever-innovative extruded and bonded aluminum chassis. I have never driven one, and I remain sad about it. Maybe if the pandemic ever ends, the nice people at the Lane Motor Museum in Nashville might be able to turn me on to their example.

I drove a Lotus Evora in Monterey in 2019. Yes, a car with a weight of £ 3,100 is lightweight these days, which sounds crazy when you say it out loud. It was great to drive, but not as good to live with as a Porsche 911. Not that you will be able to buy one for much longer: Lotus closes the production lines at its factory in Hethel, England, to recharge. for a brand new car, currently known only as Type 131.

I’m very excited to see how the Type 131 develops, as well as how Lotus adapts to life under the ownership of Geely. How it works especially with Volvo’s parts body, I’m interested – Volvo is also owned by the Chinese company. And I just realized that this means that future Lotuses will drive Android cars. A crossing of the Lotus emblem of some kind seems inevitable, which will set off all sorts of complaining. But if Porsche can make the Macan GTS good to drive, I’m not worried Lotus will cultivate its magic.

Yet Murray and Lotus are outliers, and the philosophy of lightweight has yet to emerge before it becomes a common belief in the automotive industry. But a man can dream, right?