The Economist [unpaywalled]: “…For all the safety features available in cars today to help them avoid crashes, the laws of physics are cruel. When two vehicles collide, it is usually the heavier one that prevails. This advantage has changed little over time. Thirty years ago when a passenger car crashed with a pickup truck or sport-utility vehicle (SUV), the driver of the car was roughly four times as likely to die; today this driver dies around three times as often. Critics say this is too high a price to pay for roomier interiors and more powerful engines. Carmakers insist they are giving consumers what they want. An analysis by The Economist shows that weight remains a critical factor in car crashes in America. Reining in the heaviest vehicles would save lives…Mismatches between big and small cars on America’s roads are not new. In the 1960s the 1,400lb Mini Cooper shared the road with the 5,000lb Cadillac Fleetwood and the 5,500lb Lincoln Continental. But whereas today heavier vehicles attract the bulk of the criticism, back then it was lighter ones that drew scrutiny. Indeed many cars of the time were woefully unsafe. In 1969 America’s National Highway Safety Bureau conducted crash tests on a Subaru 360 and a King Midget, two sub-1,000lb “mini-cars”. When pitted against vehicles twice their size, the tiny cars crumpled like soda cans…

Researchers also found that the safety benefits of vehicle weight suffer from diminishing returns. This means that, once vehicles reach a certain weight, packing on more pounds provides little additional safety, while inflicting more harm on others. “At some point heavy vehicles cost more lives…than they save,” wrote Brian O’Neill and Sergey Kyrychenko of the IIHS in 2004. This makes intuitive sense, says Mr Anderson of Berkeley. “Once you outweigh the other guy by a factor of two times, is adding 200 pounds more really going to make a difference for you? Probably not. But it’ll make sure that he gets completely destroyed.”