Whilst work on projections of consumer durable purchase in general was of no notable urgency during the period in question, growth in ownership of motor vehicles during the late 1950’s and its consequences for the entire socio-economic structure of western society led to this particular phenomenon receiving special attention from central governments in the UK and elsewhere. Official publication of the underlying philosophy and results of Tanner’s work on vehicle number prediction took the form of a paper in Roads and Road Construction in 1962. It is important to note the justifications for the use of the extrapolatory approach because they have remained central to the TRRL philosophy ever since, despite a consistent barrage of criticism from econometricians and others which has intensified during the past decade. It was claimed that the saturation level was even more dependent upon density and distribution of employment and population, and on quality of public transport.