Flashing the lights is quite normal here too, but nowadays it's not being "used". People are just different now. Before, you could see flashing all the time, when police was around. I'm not saying if I was speeding a lot and then you might think to yourself: "Okay, he's an idiot, he should be stopped and his license should be taken", but if you see, someone is driving normally or if you estimate, he's driving let's say 10 km/h over, then why not flash, just to warn him. Luckily, I was driving almost exactly 50 km/h there. If I had been driving 70, 80 km/h, which can be easily done there, that would be some ticket. Speeding in urban areas is here quite expensive and you can say goodbye to your license very quickly
Highways no, but urban areas, yes.
Flashing is not that against the law here, I sometimes flash and the police sees me, but never had any problems with it so far
As for the cars. There were 2 police cars parked there. White Renault Kangoo and you can just barely see the VW Touareg on the right. Look ->
I have few more videos from that trip, but didn't have the time to post them yet. But I will if you don't mind