Temporary public art
Work installed for a defined period, weeks to a couple of years, letting a city take risks, test sites, and program change into its public spaces.
Lower stakes buy bolder choices: a proposal too strange to cast in bronze for fifty years is an easy yes for one summer, and temporary programs are where emerging artists get their first public commissions. Temporary work also functions as site research: a spot that draws crowds for a temporary piece has made the case for a permanent one.
Two disciplines keep temporary programs healthy. Say the end date out loud from day one, because people grieve works they assumed were permanent. And put decommissioning in the contract (who removes it, who pays, what condition the site returns to) while everyone still likes each other.