The development of new transport systems often leads to demographic and socioeconomic changes in the implementation area. The extent and the type of such impacts vary, however, and can depend on existing settlement patterns, socioeconomic conditions, and project objectives. For a better understanding of such impacts better, this paper examines the effects of two new light rail transit lines (ML1 and ML2) in Madrid, Spain. The two lines were planned to serve different functions, and the service areas have different land use characteristics. ML1 was designed to help promote urban development in a lightly settled area, while ML2 was designed to encourage public transport in an already developed area. As expected, the analysis showed that the impacts of these two lines were quite different. Along ML1, much new development took place, and large increases occurred in the population. Along ML2, land use and population remained largely unchanged. This finding demonstrates the critical importance of integrated transport and land use planning in the development of cities.