Dude to be honest i dont know but here a solution delete the mod then install it again, if it still crashes then dont use the mod.And also these YOU HAVE TO WAIT sec BECAUSE YOUR A NEW use stuff is a little annoying but i respect the websites creator iv been on here for a little while so how long until i can be like a full member i respond to people stuff and help them out i ve been on here for like a couple of weeks now so if you could tell me when like 3 months or years from now will i be able to post without this message popping up. I know its used to prevent spammers
@player2 The only police vehicle that I know that you can "remove" the lightbar from without editing the model is the Police Cruiser (Stanier). On that car you can remove the "FLAGS_EXTRAS_REQUIRE" flag from the vehicles.meta line and after that the car can spawn without a lightbar. However, the car still sometimes spawns with the lightbar on top of it, so it won't be a permanent slicktop model.
Another way to remove the lightbar from the Police Cruiser (Stanier) is by using a Trainer. With the Trainer you can access the Car Components/Car Extras menu (or whatever they're called in the Trainer you're using) and from there you can remove the lightbar. If you want the car as a slicktop model for a screenshot/video, I recommend using this method.
But, like GTATerminal above mentioned, I don't think it's possible to remove the lightbars from the police vehicles without editing the model itself. The only way to permanently remove them is by editing the model. If you don't know/want to do it, you could try asking somebody here on the forums or on LCPDFR.com in case somebody would be able to remove the lightbars for you or already has done it in the past and would be willing to give you the model