Vertical movement is usually by mechanical means first and by foot second. Hence, lifts and escalators will need to be provided as well as generous staircases. Since they take a lot of space, they cannot be accommodated within the pavement zone of existing streets. The usual answer is to create a square or piazza at the interchange ground entrance with the vertical means of access dropping down from this space in a functionally and visually coherent fashion. Normally, the ticketing and bridging zone is 6-7 metres above the track, which results in a mezzanine format midway between ground and track level. Here, the public facilities of shops, cafés, toilets, travel information and ticketing are located with a roughly equal distance vertically to the street above and the tracks and platforms below. So the role of the urban square is to signal the location of the routes down to the interchange and to handle the surface movements both on foot and by wheel. Often a
structure will be required to house the stairs and lift and this will need to be eye-catching in order to aid use legibility.