>>>>"The body and frame are designed with crush/crumple zones and roll-over protection, and the tandem seating means large side crush zones. Volkswagen claims protection comparable to a GT racing car. The car has anti-lock brakes, airbags with pressure sensors, and stability control." - in a car that weighed 290kg empty.
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>>Trouble is that the laws of physics are more interested in mass and momentum than in crumple zones. When a two-ton behemoth rear-ends the 290kg vehicle, the lighter vehicle changes trajectory quickly enough to disengage neck vertebrae while the SUV driver brakes to a halt and says "ooh, what was that."
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>As a mechanical engineer I understand that argument, and it's true that a safely-designed massive vehicle fares better than an equivalently safely-designed light vehicle in the general case.
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>To be precise, crash safety primarily boils down to two things:
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>- providing a cell that resists deformation and penetration, thereby mechanically protecting the occupants
>- keeping acceleration forces below critical levels
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>In your example the light vehicle would be accelerated from zero to (say) 50 km/h in the length of its rear crumple zone. It's not impossible to manage that; YouTube has examples of stock and Indy cars hitting the wall at 150+ km/h (accelerating from that speed to zero in the length of that vehicle's crumple zone) with the driver basically walking away.

Formula 1 has come a long ways since the 70's as far as making the sport safer. The cockpits are amazing https://www.formula1.com/content/fom-website/en/championship/inside-f1/safety/cockpit-crash-tests/Cockpit_safety.html
..also keep in mind these guys are wearing helmets and such too. The idea is that you want the car to disintegrate so the driver does not. This can be problematic on the track because at the same time you don't want a bunch of car parts flying around at 150+mph either. Wasn't too long ago a driver lost his life because part of his suspension ended up hitting him in the head when he hit the wall. (one of the dangers of open cockpit race cars). F1 i s looking into having partly closed cockpits now http://www.theverge.com/2016/2/24/10858548/f1-closed-cockpits-cars-fia-halo