The impact of orbital motorways on intra-metropolitan accessibility: the case of Madrid's M-40

In this paper, we analyze the impact of orbital motorways on intra-metropolitan accessibility, using as an example the Madrid M-40 orbital motorway. The maps of changes in accessibility show that, as one might expect, the nodes situated near the M-40 are those that most benefit from the new infrastructure and that the further their distance from the M-40, the weaker the changes, although the gradient is much steeper towards the city centre than towards the exterior. All the indicators used point to the fact that the new orbital motorway has brought about relevant changes, but the intensity with which such changes are registered depends on the variable used as a mass (changes are higher in accessibility to population indicators than in accessibility to employment indicators), and on the type of operationalization adopted (the most complex ones are those which least noticeably reflect the effect of the new orbital motorway). It has been verified, in the case of the Madrid M-40, that orbital motorways do not necessarily lead to an increase in the equality of intra-metropolitan accessibility, for this will depend on their location within the metropolitan area: the further out they are, the greater equality they bring, even though they attract less traffic.