Intra-household interactions in transport research: a review

Recognition that individuals do not make their travel decisions in isolation of the household context has produced a growing interest in intra-household interactions and group decision-making. The behavioural realism of travel demand models that explicitly accommodate intra-household interactions is expected to provide more insight into travel behaviour and a more credible analysis of travellers' response to transport policy than models that deal with household interactions in a 'black box'. This paper reviews the literature on group decisions and intra-household interactions. How intra-household interactions influence the way in which decisions are made is expounded and empirical findings are drawn upon to argue for why the study of intra-household interactions is important. Various analytical techniques and data requirements are discussed to show how intra-household interactions can be handled. Drawing on this review, the impact of intra-household interactions on travel behaviour and implications for transport policy are identified and directions for further study suggested.