waron501

Yes.  FiveM specifically states you need a clean, unmodded GTA directory.

If you're lazy like me, there's also the "Cops: Back on the Beat" mod. It allows police vehicles to spawn into traffic and spawns police foot patrols. I love it because when I initiate a pursuit, or someone starts popping off shots, you don't even need to call backup. You'll see units get involved from all over the place. You'll see other units pulling out of alleys and other roads heading the same direction you are, to the same scene. You'll see the foot patroling officers run towards the scene with their weapons out. If you're in a pursuit, gradually more vehicles will get involved.
 
It's also more realistic. When you need backup in real life, you don't just press a button and a unit appears around the corner; then you press it three more times and three more appear around the corner. Units respond from their current location, and they may not anywhere nearby. When you need help, you just have to wait and gradually units will show up on their own and get involved. I have a lot of fun with this.
 
https://www.gta5-mods.com/misc/cops-back-on-the-beat

@HemiPursuit Or when you do a traffic stop and you call a code 2 backup they come down, park in the middle of the street, sit in their car for about 20 seconds  and drive off...