# Towards Sustainable Regional Planning: Potential of Commuter Rail in the Madrid Urban Region
## 2 Materials and Methods
### Research Methods  
To address the first research objective--i.e., to investigate and describe the land occupation and mobility patterns in the Madrid urban region--three core factors are taken  
Figure 1: The Madrid urban region and the commuter railway network. into consideration from a diachronic perspective (1990-2018): land use, the amount of artificial surface; basic sociodemographic data, the number of inhabitants and jobs; and some basic travel data, including the number of trips, transportation mode (private vehicle, public transport, others) and the origins and destinations (Madrid city, metropolitan belt, regional belt, or outside the autonomous community). These three factors have been used to characterise the sociospatial transformations in previous studies; this study, however, considers the three of them simultaneously and investigates their evolution for different time intervals, depending on the available data. To investigate the evolution of the artificial land surface, data from the Evolution of Land Use in the Community of Madrid (1956-2005)--Evolucion de la Ocupacion del Suelo en la Comunidad de Madrid (1956-2005) [38]--and CORINE Land Cover [39] in 1990 and 2018 were used. Artificial surface is a direct indicator of urban expansion. For this work, artificial surfaces are grouped using three of the four categories that CORINE Land Cover identifies as artificial surfaces: urban fabric (areas mainly occupied by dwellings and buildings used by administrative/public utilities, including their connected areas); industrial, commercial and transport units (areas mainly occupied by industrial activities of manufacturing, trade, financial activities and services, transport infrastructures for road traffic and rail networks, airport installations, river and sea port installations, including their associated lands and access infrastructures); and artificial non-agricultural vegetated areas (areas voluntarily created for recreational use, including green or recreational and leisure urban parks, sport and leisure facilities). The fourth category--mines, dump sites and construction sites--was not considered. Population data were obtained from the National Institute of Statistics, Instituto Nacional de Estadistica, through the Population Census, Censo de Pollacion, and the Continuous Population Register, Padron Continuo [40]. Data on the employed population were obtained from the 1991 Population Census; for 2018, the data were obtained from Social Security, Seguridad Social, affiliates provided by the Ministry of Inclusion, Social Security and Migration [41]. Mobility data was acquired from the Household Mobility Surveys, Encuestas Domilarias de Movillado and prepared by the Planning and Coordination Commission of the Metropolitan Area of Madrid, Comision de Planeamiento y Coordinacion del Area Metropolitana de Madrid (COPLACO) in 1974 and 1981 [42] and the information prepared by CRTM in 1996, 2004, 2012 and 2018 [43]. (COPLACO was an autonomous body, of an urban nature, of the State Administration. It was created by law in 1963 to \"promote, agree, guide, coordinate and supervise urban planning\" within an area that included twenty-three municipalities located around Madrid, including that of this city. In 1983, within the process of building the State of the Autonomies, the functions of COPLACO were transferred to the Autonomous Community of Madrid) The data obtained from the Household Mobility Surveys in 1974 and 1981 consider the metropolitan area defined by COPLACO at that time, while the data subsequently obtained pertain to the urban region delimited by CRTM and were divided into fare zones. To approach our second objective, we concentrated on the situation in 1991 and 2018 and examined the changes in this period in terms of population, employment, and artificial land, differentiating and comparing municipalities with and without stations. We characterized the municipalities of the Madrid urban region based on their population and employment densities and compared those with and without stations.