Wow that sucks man. if you're going to drive with anything on you, take special precautions. It's best just to stay home and watch a movie when you're high. Also since cannabis is a "controlled substance", which it really isn't, there are no legal guidelines or limits for them to say that you were intoxicated on cannabis, as they can do with alcohol with a breathalizer. But remember these things when you get pulled over or are in any situation with a cop.

- Be calm and respectful always to the cop. It will reduce his anxiety level on you so he knows your both cool.
- Know your rights. Never consent to a search. Simply tell him that you wish to uphold your 4th Amendment right and do not consent to a search of you or you're belongings without a warrant...period!! Thats how most people get busted because they do not know their rights. When cops know that you know your legal rights, they will be way more cautious. If he gives you a hard time which they usually do, just say "I wish to remain silent and will not speak without a lawyer present from here on". Remember this is your right!! Don't be intimidated by a cop no matter how much authority he has. They know they really can't touch you if you do not consent to a search. The Constitution is the Supreme Law of the Land.