It is actually quite simple. You just provide legislation that allows for councils to issue a 'temporary traffic control order' that enables a stated person to supervise traffic controls according to the attached schedule at the specified location at the specified time. This would be simple, a sign saying 'caution. Traffic control ahead', a second saying 'wait here when instructed' and a suitably clad person with a stop go board.
It could be used for everything from a road race (running or cycling), moving large and complex loads, work where traffic would be endangered (ie tree felling), parades crossing a main road etc. It would formalise the informal that happens day in and day out. It enables that gap between needing a full road closure and minor delays of a few minutes.
Yes we cannot legally stop traffic, but we can politely ask drivers if they wouldn't mind waiting a couple of minutes. Most are more than happy to do so but there are always some who will insist that they have a right to proceed at the speed limit irrespective.