All infrastructures have their own unique characteristics that influence their operation.

Calle 30 has a 40 km network of tunnels that are the largest urban tunnels in Europe and have a very high traffic volume. These tunnels were built along the banks of the Manzanares river, with a large part of them below the water table. The Madrid Río park was constructed above the tunnels and provides access to many of the technical rooms for the tunnel’s installations. Calle 30 is a ring road that surrounds Madrid’s ‘almendra central’ zone and acts as the final entry barrier to Madrid without restrictions from an emissions perspective. Calle 30 experiences a high volume of traffic, especially during rush hour periods Mondays to Fridays (excluding bank holidays). All of these factors affect the way in which Calle 30 is operated.