How to make regular traffic cars into police traffic

I basically want some regular cars to behave like police cars when the ai traffic mode is active,
How could i do that?
thank you!

 

Attach a siren to normal cars, about the best you can get,

 

how can i do that?

 

Through the parts selector, search siren. Not every car comes with one

 

ooh i understand thanks for the suggestion, i wonder if it can be done with some code in the vehicles forder to make the car looking completely stock

 

You could make a siren add-on mod that equips the part, but has no model or ability to play audio. It'd simply be something that goes into the slot for the light bar.