For a certain number of years now, France has been undergoing an ageing of its population. This ageing, which is going to become greater and continue over the coming decades is accompanied by profound modifications in the life styles of retired people. They are more and more motorised in the cities and less and less prisoners of the necessity to walk or use public transport. In this paper we will try to study the changes in the mobility of the elderly using diachronic data obtained from household surveys carried out in the seventies and eighties in the Grenoble conurbation. At analytical level, the factors explaining these changes can be linked to the renewal of the generations and the modification of the socio-economic environment which counter the ageing effects. We first situate the travel pattern and modal use evolution of elderly people within the context of the population as a whole. We then go on to deal with the central question in the evolution of the modal distribution, i.e. the individual's access to the private car, and its daily use. The longitudinal study of the successive cohorts enables us to visualise the differences in behaviour between men and women on the one hand, and the determining character of the development of car ownership for successive generations on the other hand. Using a breakdown of car driving into three effects (demographic, ownership and actual use of cars) we show that it is the increase in car ownership, much more than the other two effects, which leads to an increase in car driving after the age of sixty. The same type of analysis applied to people who are presently in the 40 to 60 age-group shows that women, who drive relatively little for the moment, are rapidly going to catch up in the future.
