More than two thirds of travel mobility is directly or indirectly related to social purposes. However, research so far has disproportionately concentrated on work related trips. This project aims to redress this unbalance and explore the implications for the achievement of sustainable mobility. Using data from the innovative LISS panel, we investigate the causes and consequences of mobility in social networks in terms of the frequency and distance of trips and the choice of mode of transport. Special attention will be paid to the relationships of mobility with car availability, accessibility by car and public transport, and local mobility policy.