This article investigates transitions at the level of societal functions (e.g. transport, communication, housing). Societal functions are fulfilled by socio-technical systems, which consist of a cluster of aligned elements, e.g. artefacts, knowledge, user practices and markets, regulation, cultural meaning, infrastructure, maintenance networks and supply networks. To understand how transitions from one socio-technical system to another come about, the article describes a conceptual multi-level perspective. The perspective is illustrated with a historical case study: the transition from horse-drawn carriages to automobiles in the USA (1860-1930). The case study shows that technological substitution approaches to this transition are too simple, because they neglect the electric tram and bicycle, which acted as important stepping stones. The case study also corrects another mistake, namely that the gasoline car won by chance from steam and electric automobiles. It will be shown that particular niches played a crucial role in this competition, as well as the wider socio-technical context. The case study deviates on three points from the multi-level perspective. These deviations are used to conceptualize a particular transition pathway, called 'de-alignment and re-alignment'. © 2005 Taylor & Francis.