The objective of this paper is to estimate the factors that determine non-use of the private car among young adults and to measure the specific effects of accessibility and urban form of both the area of residence and work or study. The analysis is based on two recent Household Travel Surveys conducted in the Lyon conurbation in France in 1995 and 2006 which have been enhanced with contextual indicators extracted from geographical databases. Three modes frequently used for home-to-work/college trips have been considered: the private car, public transport and active modes (walking, bicycle). The results from multinomial logit models show that socioeconomic factors have a significant impact on modal choice for home-to-work/college trips. However, the characteristics of an individual’s areas of residence and activity still have a strong explanatory power for non-use of the private car among young adults. The influence of the urban structure via population/employment density, nearby facilities and public transport accessibility was even greater in 2006 than in 1995. The likelihood of not driving among young adults nonetheless depends much more on the public transport accessibility and the urban structure of the area where they work or study than that of their area of residence.