A tram stop is a place designated for a tram to stop so passengers can board or alight it. Tram stops share most characteristics of bus stops, but because trams operate on rails, they often include railway platforms, especially if stepless entries are provided for accessibility. Trams are perfectly capable, however, of stopping at mere bus stop-type flags and using pavements as platforms, as seen, for example, in Budapest. Most tram stops in Melbourne have no associated platforms and stop in the middle of the road; traffic cannot pass a tram with its doors open unless the tram is behind a safety zone. On the other hand, Manchester Metrolink high-floor trams stop at dedicated platforms at the height of a railway platform, because the tram system took over former railway lines in the suburbs. Such trams also stop at dedicated platform stops on Stadtbahns in Germany, especially in underground stations in the city centre.