The joke is that
some people get together somewhere and map out a place to set up cones and tear up the road. Setup then involves blocking off a half mile strip of road on either side of the workzone, and proceeding to jackhammer the hell out of the asphalt.
The punchline is everyone that has to drive through the workzone, as the workers not jackhammering (all of them) laugh at the frustrated looks on peoples faces as they go by, late for work by at least half an hour or more thanks to a four lane highway being shrunken to one lane.
Once the “work” is supposed to be done, or when a new place is found, the workers pull up stakes and move, leaving the road the same as it was before they came, or worse.
This has been going on since before recorded history in Utah, although no record has currently been found as to whether it started with the laying of asphalt in Utah, or merely when roads were established.