As a traffic calming device for Grote Marktstraat, OMA have shifted public transport and motorized traffic onto various levels underground. A tram service plus two stations and a double layer of parking occupy a ‘tunnel’ of 600 x 15 x 12 metres. The key task of the service tunnel is to tie together the various underground parking facilities and the retail premises in adjoining buildings. Visual and physical links have been forged between the levels below-floors and the world above. Construction of the tunnel was dogged by technical problems setting back the completion date by several years.