I know for a fact that some owners of large 4×4 vehicles specifically buy them because they imagine that they’ll be safer than in a smaller car. Of course, they’re quite wrong.
In fact, the “consumer” 4×4 was actually invented in order to circumvent safety legislation. American maufacturers originally managed to have their products classed as light commercial vehicles, which made them exempt from the expensive testing required for regular cars.
These days, all our vehicles are tested for safety, and although big 4x4s have often done spectacularly badly, modern ones are now probably almost as safe for the occupants as ordinary cars. There is one exception: they’re about twice as likely to roll over in an accident than is a car.
Because the larger body shell is inherently less rigid than the body of a smaller car (think of a large floppy cardboard box versus a small rigid one), it is then more likely to collapse and injure the occupants.
Some 4x4s are still designed, like the early ones, with a stiff “ladder” chassis that carries the engine and wheels, and the bodywork attached on top. The cabin is even less rigid than ones designed like modern cars, which have a stiff unitary bodyshell. (Have you seen the video of a demolition ball hitting a Smart?)
Statisically, and curiously, 4x4s are involved in more accidents per mile than most other vehicle types. Perhaps it’s the drivers’ false sense of security that leads to risky behaviour (a well-researched phenomenon). Some additional factors have been suggested, such as blind spots due to the large bodywork, and drivers’ lack of awareness about how big the bloody thing actually is.
Obviously, it’s not just the occupants who are at risk. In accidents involving pedestrians, they’re likely to be much more badly hurt if hit by the high, flat front of a 4×4, and there is still a large difference between official crash test ratings for 4x4s compared to conventional cars.
Some owners like to ensure a definite kill by attaching “bull bars” to the fronts of their vehicles. They were invented in Australia to mitigate kangaroo collisions in the outback, and were named “roo bars”. Even the idiots who buy them in Europe weren’t going to fall for the story of kangaroo danger, hence the marketing re-branding as “bull” bars, as if colliding with a bull was a more likely risk. I call them “child killer” bars.
In an accident with another car, the old “ladder frame” design is particularly dangerous, because the ladder can spear right through the other vehicle.
I have a 4×4 vehicle (just a little one). I don’t dream for a moment that I’m safer in it than I would be in any other car.