In the 1960s the Institute for Safety in Mining, Industry and Transportation was one of several technical surveillance organizations in the Federal Republic of Germany. An aim of the transportation division was to find ways of identifying motorists who were at risk of collisions because of a tendency towards inappropriate behaviour in traffic. Psychologists at the Institute were working on developing objective instruments to measure the psychological attributes that predispose an individual to such a tendency. At the time there were few psychological measuring instruments that had been empirically tested specifically for their utility in the prediction of safe or unsafe driving behaviour. Accurate prediction of any aspect of behaviour requires firstly that the attribute to be measured is relevant to the behaviour in question and secondly that the construction of the measuring instrument results in robust measurement of the attribute.