Dutch national accident data show a considerable increase of the number of rear-end collisions during the last 10 years. Also the numbers of cars involved and casualties from these accidents have increased. Neck injuries, typical for rear-end collisions, are expected to become a major health problem, though it is still very difficult to obtain reliable data.
Head restraints, meant to prevent neck injuries during rear-end collisions, are not compulsory in The Netherlands. Traffic observations show, however, that they are available in nearly all modern cars. Their proper adjustment appears to be a great problem. A great number of occupants (both drivers and front seat passengers) are not adjusting the restraint as it is should be, i.e. the top of the restraint is positioned lower than the top of the occupants’ ears. The problem may be partly due to incorrect positioning of the restraint by the occupant. On the other hand, the problem may be caused by insufficient maximum height of the restraint. Calculations, using population measurements, have been carried out and it was found that for Dutch male occupants the minimum height of head restraints (as regulated in ECE 25) should be increased considerably to satisfy all but the highest 5-percentile of the population.