Some aspects of the legislative and political process leading to the adoption of a seat belt law in Britain are outlined. The technical arguments in favour of such a law were successful in debates in which the freedom of choice was the main substantive counter-argument. The economic aspects of the decision were vital as were the outside influences of the specialist organisations and the media. Early indications are usage rates rising from 40% to 90% with the introduction of the belt law, and for the first five months of operation a reduction in fatal and serious casualties of some 20%. Control casualties, represented by rear occupants and pedestrians and motorcyclists, increased due to seasonal factors and therefore the 20% reduction in front seat car occupant casualties is probably conservative. Some post-law problems of belt use for small pregnant women and arthritis sufferers are mentioned, together with the difficulty of facial injuries to restrained drivers from steering wheels. The policy choices of seat belt laws and passive restraints for the United States are discussed, and the great importance of belt laws to cover the period of at least a decade of lead time necessary for the passive restraint option is shown to be vital.