BIM mandate
A government requirement to use BIM on public projects — the main engine of adoption, solving the collective-action problem of a fragmented industry (the UK's 2016 'Level 2' mandate was the influential template; dozens of countries now have roadmaps; India's MoHUA mandates BIM on large central projects). A mandate accelerates adoption but doesn't guarantee good BIM — firms can comply on paper and miss the value.
