Pedal cycles in the Channel Tunnel are normally only allowed to cross the Channel Tunnel fixed link between the United Kingdom and France using the Eurotunnel cycle service, on board a Le Shuttle train. This consists of a minibus and bicycle trailer for six bicycles. On a number of special occasions since 1993, crossings have been made directly using the bidirectional Channel Tunnel service tunnel, positioned between the two rail tunnel bores. This central service tunnel has airlocks at both ends, and a concrete screed road surface.