I was driving thru Idaho on my way to Montana (California plates and I have long hair) and an Idaho cop came out of the center divide onto the freeway after I went past (I was doing exactly the speed limit). He pulled up along side of me for a few seconds and then dropped behind me and pulled me over. He said my eyes were red and he thinks I've been smoking pot. I told him I don't smoke pot (I don't). So he asked what prescription drugs I am on. I told him he had just pulled over the most anti-drug person he was ever going to meet - I drink carrot/celery juice and the closest thing to drugs I use is vitamin C. He held me there for over 30 minutes and asked me over and over when was the last time you smoked pot? (I told him 1968). I've done some Google searches on this and learned that they take a training course on recognizing drug use just by looking at you and they can arrest you for driving stoned going by nothing but how you look to them "because of their special training" (and because there is no test they can give at this point). I didn't argue at all with the guy, stayed polite. I even requested a test "please give me a blood or urine test and you will find that I have no drugs of any type in my system". He finally let me go on my way but never apologized.