[JaTochNietDan]

The problem is that you're comparing the model of the vehicle to the ID of the vehicle.

pawn Code:

if(GetVehicleModel(GetPlayerVehicleID(playerid)) == Cars[Police])

You could either change == Cars[Police] to be the model ID of the vehicle, or you could simply edit it to work with the way you have it set up

pawn Code:

if(GetPlayerVehicleID(playerid) == Cars[Police])

Also there's a problem, you only have one variable for the vehicles, so basically Cars[Police] only contains one of the vehicle ID's (the last one you set it to). The only solution to this is to make Cars[Police] an array, and store multiple vehicle ID's in the array, then use a loop to go through them. This is a bit too much for something that can be done a lot easier and more effectively, so I recommend the simple solution which is something like.

pawn Code:

if(GetVehicleModel(GetPlayerVehicleID(playerid)) == 596)

Add if you want to check more models, you'd need a loop or just a long list of checks on that line.

pawn Code:

new model = GetVehicleModel(GetPlayerVehicleID(playerid));
if(model == 596 || model == 427 || model == 601 || model == 599)

Edit: Someone else also showed you how you can do it with a simple switch statement, either way will work however the switch statement would be cleaner.