'Is that typical police cars?' Can't answer that one.
But C-Max mileage goes down in the winter. Why? Because heating the car can't be done well with a battery so the C-Max fires up the engine to give you heat. I keep my car cold (my wife gets irritated) and my mileage is substantially better than my wife's (we both have C-Maxs).
The less you run the AC or the heat the better your mpgs. And using the terrain (letting off on the gas when going downhill and building up speed before uphills).