W - Whiplash
Whiplash/whiplash rating - Whiplash injuries can occur when your head is thrown back violently in an accident - usually following an impact from behind - causing the neck to deform into an S-shape. Such injuries can be avoided, or at least minimised, by making sure your head restraint is correctly adjusted. (See Head Restraints.)
Whiplash rating - These ratings are set following research by Thatcham on brand-new cars (see Thatcham).
They are based on two measurements: first, the height from the top of the head of an average-size male to the top of the head restraint should be no more than 6cm. Second, the distance from the back of the head to the front of the restraint must be as small as possible.
Each restraint is classified as Good, Acceptable, Marginal or Poor. (See www.ncwr.co.uk.)