If there's a mod I like, it's Emergency Lights Mod, however, it's made for SA-MP, so there are a lot of bugs in SA Single player. But good news, I'm creating one myself, with giroflex, and such, and a version simpler to use, without many texts, without menus etc, the mod is on its 3.0 version,and it already works very well.
For now the mod is only available for PC, but I intend to port it to ANDROID
REQUIRES MODS:
CLEO+

Tutorial to convert cars : forum.mixmods.com.br/f92-tutoriais-utilidades/t8106-how-to-convert-cars-to-sirens-lights