The advantages of orbital ring roads as regards private vehicle mobility are clear (Madrid has two orbital motorways, M-30 and M-40, and another M-50 under construction). These infrastructures seem insufficient in the case of public transport. Most world underground networks are radial-based, connecting peripheral quarters with city metropolitan cores. In keeping with the evolution and consolidation of these underground systems, it has been necessary to set up some additional transversal lines. Likewise, strictly speaking, only a few cities can be said to have orbital lines connecting the different sections of the underground network. Madrid was one of the first cities to consider the chances of implementing an orbital line as a key factor in public transport networks. Today, the city affords both an underground and an urban bus orbital line. Madrid orbital Metro Line 6 - running 24 km along 27 stations - has the highest passenger flow. Its orbital structure allows the highest distribution of trips, both urban and metropolitan, favouring thus the cross-sectional movements and facilitating transmodal trips. In this regard, the new line has brought about an increase in multimodal trips both to other underground lines and to other transport modes. The amount of data collected from surveys, prior to and following the completion of the loop, provides some new and revealing information for the assessment of the project's impact on the general mobility and also on the operational aspects of a circular line, both in terms of demand and supply. This paper puts forward some of the effects on public transport demand associated with the implementation of the line. Special attention has been paid to the transmodal connection analysis that has been conducted on the Circular Line and on some other underground lines and transport modes.
Abstract