According to medical websites, marijuana traces can stay in your system longer than 30 days. My question is...If a person that has a valid user card "uses the drug" does that mean they can't drive? If the drug stays in your body that long how could they tell if that person was "really" under the influence or just has been in their system for a month. I imagine that many people drive while under the influence of legal prescription drugs like vicotin..

How will the police be able to tell if someone is driving under the influence of marijuana as the THC can remain in the body for up to four weeks after using it just once? I hope they don't abuse this fact as anyone pulled over that is a card holder will always be found "under the influence" in their book and they would gladly hall them to jail!!

The people of Michigan have spoken with their vote, in a free and democratic republic, so the new law is now law, period. Let the newby get a test drive before ya'll codemn it so quickly. My dad had a saying, "don't cross bridges before you get to them": i.e., don't worry and fret about something that hasn't even happened yet. Or, you could watch that good old movie sponsored by the Feds. called Reefer Madness, made in the 1930's or so. That Maryjane will ruin society forever and make killers out of anyone whom tries it. We have come a long way since the 1930's, or at least most of us have I hope. Besides, from what the article here states, it is going to be very strictly prescribed, and has many restrictions, unlike California's clinic giveouts. Many with medical problems need the chance to get pain relief, chemo relief, as well as glaucoma patients. I think Michigan's approach is more than fair, practical, and conservative to say the least.

I just read where the law enforcement agencies are now training special officers as (DRE) Drug Recognition Experts in Mass. and Cal. with an 84% success rate in convictions. The officer has special training to recognize drug influence of the subjects with a host of identification tests: eye motion/clarity, speech, thirst, hunger, pulse rate, blood pressure, signs of syringe usage, and various lab tests with blood, urine, and hair. Seems this is a good place to start for Michigan Police agencies. There are several agencies, universities, private corps., and doctors working on the pot breathalizer already and should have something on the market soon. An interesting challenge for the future.

It's going to be quite a challenge for the law enforcement agencies as well as the medical users of this substance for the near foreseeable future without a guage of sobriety to measure with. This should be a real inventor's dream: i.e. how do we manufacture an instrument like a breathalizer to determine sobriety of marijuana smokers. The guys that do come up with a system that works and meets court/state regulations, are going to make hundreds of millions of dollars in a short few years. Now let's see, back to the drawing board, I think we should .......hmmmm.......

Cannabis has been used for about 4,000 years for medical purposes. In Taiwan about 10,000 years ago the people of that country used marijuana for fiber. It’s important to mention that it’s not the social threat authorities believe it to be. On http://medicalpot.com . you can find out more about the wide range of medical applications of pot in treating diseases such as convulsions, asthma, anxiety, nausea, vomiting, schizophrenia.

Sweet Madical Marijuana!!!! Idiots!!!!