We investigate the effects of highway improvements on the
suburbanization process of Spanish metropolitan areas between 1990 and 2006. We use an intrametropolitan approach focusing our analysis in the suburbs with the objective to add new evidence of the phenomena at a smaller geographical scale. We analyze the suburbanization process using data on population and residential land use to be able to control not only changes in location patterns, but also changes in land consumption patterns. Compared to other studies we address the endogeneity problem with a set of new historical instruments that could improve the quality of the estimations:
the Roman roads, the 1760 post routes, and the 1984 National Road Plan. The results show that highway improvements foster suburban population growth, but not suburban residential land growth.