The Autoritat del Transport Metropolità (Metropolitan Transport Authority or ATM)
is a voluntary inter-administrative consortium set up in 1997, which all
administrations can join that own collective public transport services,
individually or via groups or bodies that represent them, which belong to the
area comprising the counties of Alt Penedès, Anoia, Bages, Baix Llobregat,
Barcelonès, Berguedà, Garraf, Maresme, Moianès, Osona, Vallès Occidental and
Vallès Oriental.