[SilentSoul]

pawn Код:

CMD:siren(playerid , params[])
{
    if(!IsPlayerInAnyVehicle(playerid)) return SendClientMessage(playerid,0xFF00000FF,"You're not inside a vehicle");//checking if the player inside any vehicle you can customize the model by using GetVehicleModel function !=
    new SirenObject,VID;//declarying
    SirenObject = CreateObject(18646, 10.0, 10.0, 10.0, 0, 0, 0);
    AttachObjectToVehicle(SirenObject,VID, 0.0, 0.75, 0.275, 0.0, 0.1, 0.0);
    return 1;
}

Sources : https://sampwiki.blast.hk/wiki/IsPlayerInAnyVehicle
https://sampwiki.blast.hk/wiki/AttachObjectToVehicle