If a seat is too stiff, without enough 'give' to it so a person sinks into it during a crash, then the head restraint can move back and away from the head. This can lead to higher forces on the neck, and whiplash injury is more likely.

It's now rare for a vehicle to earn a rating of anything less than good in the frontal offset crash test.

But good head restraint geometry by itself isn't sufficient. A seat has to be designed so it doesn't move backward and away from the head during a rear impact. A seat also needs to 'give' so an occupant will sink into it, moving the head closer to the restraint.

The sled test simulates the kind of crash that frequently occurs when one vehicle rear ends another in commuter traffic. People think of head restraints as head rests, but they're not. They're important safety devices. You're more likely to need the protection of a good head restraint in a collision than you are to need other safety devices because rear-end crashes are so common.

Bumpers that bump apparently weren't a consideration during the design phase ... Designing good bumpers is no great engineering challenge ... but unless this is a priority we're going to continue seeing many manufacturers using inferior designs.

The four-point harness would be protective, but not as big a benefit as it would have been before airbags.