That’s a mouthful, but this example from Ohio clearly shows how short term projects of just a day or two can help stimulate lasting change in urban environments. https://www.strongtowns.org/journal/2018/5/9/4-permanent-impacts-of-temporary-tactical-urbanism-projects
There are more details at https://www.betterblock.org/
And of course in the UK there are traditions of street markets, play streets and street parties as a way of temporarily changing how a road is used and putting it over to people.
The design and use of urban spaces will be explored at the next Big Local environment cluster event which Julian and colleague Margaret Jackson are running on 8 July in Sheffield. https://localtrust.org.uk/big-local/events/environment-cluster-lived-environment-and-the-public-realm/