I know in Pa. they had a mile buffer zone to where they could pull you over and write tickets. Anything past that they had to wait for that town/counties cop to come.

Also if you see an out of town/county cop usually they're transporting a prisoner, or going home if they live in other counties. Thats if they're permitted to drive the cruiser home. Some are back home Idk about here. Or they were meeting other officers for Lunch. lol