Overtime is usually discussed as a payroll number at the end of the month. By then it is history. It was decided the week before, when the routes were built.
Why it matters
Overtime is paid at a premium for the least productive part of the day: the end, when the technician is tired and the remaining stops are the ones that did not fit. It is the most expensive hour you can buy and it buys the worst work.
It is also a retention problem. Technicians rarely leave over pay alone. They leave over unpredictability — not knowing which evenings they get back.
How you notice it slipping
Overtime is treated as a cost to control rather than a plan to fix. It concentrates on particular routes or particular weekdays. The same two technicians produce most of it, and the explanation given is that they are slower.
What to do
Add up planned service time and planned drive time per route before the day runs, and compare it against the hours available. Where the sum is already over, no amount of effort on the day will rescue it. Fix the plan; the hour was committed before anyone turned a key.