In this collection of screenshots I have simulated the police escort containing diplomats in the limousine.
This simulation is performed as I happen to sometimes see the police escort in my country.
They maybe escorting gov't people, popular artists, prisoner transport, or VIP.
Well, this is quite simple, however. The driver in the limo didn't turn both indicator lights on and beeping.
You will also notice taxi bug in my screenshots. Don't worry. If you have installed RIL.Budgeted or any traffic fix script, then you won't see this problem.