Not long ago, something similar happened in my country with garbage collection. They noticed that the staff completed all the assigned areas much faster than predicted so... they assigned almost twice the workload to each of the trucks. The result? A massive strike because workers were able to prove that the new schedule was impossible to follow without rushing.
Twice the workload is a pretty extreme example. They could likely have boiled the frog - You're doing 25% longer routes this year, then another 25% the next, gotten real efficiency gains, and gotten reasonable pushback when they did.
A strike is the right option, but strikes are good for nobody. It's crazy how often management these days has just zero clue.
