Social activities are responsible for an important share of trips conducted by individuals. This paper contributes to a rapidly increasing stream of transportation research into individuals choice of social relations and trips made to maintain their social relations. This paper will describe a method that was used to collect data on ego-centered social networks in a large-scale survey conducted in the Netherlands in the late eighties and propose a model-based framework to analyze this data. The framework consists of a set of linked regression and choice models to analyze and predict in a coherent fashion travel demands resulting from a chain of decisions including the size and composition of the social network and travel time and contact frequency related to each member of the network. The results indicate that socio-demographic attributes of an individual have only a modest influence on network size and a stronger impact on the choice of relationship type, travel time and contact frequency. Furthermore, significant relationships exist among these social-network variables. The paper will conclude that the framework provides a straightforward and useful way to analyze social network data and identify fruitful ways for future research.
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