The best way to test citycars is to remove the citycar pak file (BritCitycar.pak) and then create a pak file with just the cars you want to test. Start a game, and switch to public player, then use the add citycar button to create loads of citycars (obviously only the citycars you created will be allowed). If you build them on a circular piece of road, they will have no choice but to follow all 8 rotations at some point.