We have an HS2 dig locally. They often send us notification of predicted road closures. Then completely ignore them. They do take time out to set up the completely nonsensical diversion routes though. Then close the relevant road without notice and wonder why nobody wants it.
My local High Street has a mini roundabout at the North end, a crossroads around half-way along, and a light controlled crossroad at the bottom. There were three lots of roadworks running in the area, all with the High Street along the suggested routes. Very cleverly, this meant Diverted Traffic signs were set up for all of the directions at both crossroads and at the roundabout. Apparently, when challenged the Borough said they were not responsible - for their own roadworks!
This might be true - I read somewhere that, planning, signage, diversions, and so on is out outsourced. Frequently digging the hole is outsourced, the work to be done is outsourced, and the backfilling and making good is (wait for it) outsourced.