As I drive frequently, I am stopped frequently - usually for speeding. The best advice to foreigners that I can give is, when stopped by the police, be sure to speak absolutely no Bulgarian - even if you can. Even a basic understanding of the language is a sure indication to the police that you should know better than to break the traffic laws. You might even try saying in your most innocent mid-western American accent (if you can do one) " I am sorry officer, but I just don't understand... I am sorry... what". Complete ignorance is the best defence.