Keeping track of the number of times someone says dude ought to be sufficient...

My bet is that prosecution will be limited to those who get pulled over for driving erratically coupled with the presence of the odor of marijuana when they roll down the window for the cop. They will probably develop a field test of some sort. Blood shot eyes, inappropriate comments, laughter, etc. Even then it will be hard to prove beyond a reasonable doubt that they were under the influence. Our current BAC level of .08 is a statutory presumption of intoxication. Pot effects people differently. The nature of the high changes depending on the strain of the weed, and a person can get totally stupid after taking a single toke of the strong stuff. Chronic smokers have a much higher tolerance, and THC levels in their bodies don't mean much in terms of being under the influence. I can't imagine how testing a person's blood, urine, etc. would do much good.

...forgetting to open the garage door when driving out... (To quote Bill Hicks, "We've got to open the garage door so Domino's knows we're home!")

When a cop pulls you over and asks you to stand on one foot without teetering, be sure to say, "I can't do that when I'm sober!"

Or, from the U of O Student Athlete's Handbook, when asked if you are in possession of any maryjane, respond: "No! we smoked it all, dude"

Watch all Chech and Chong movies for clever responses.
Oh wow! man it's goona be hard to remember all that stuff, man.

Good points Kevin. The prosecution will still have to prove impairment, and there will be no test similar to the BAC test to measure legal limits. They will have to rely on roadside tests.

I would suggest new ones:

1. Provide the driver with a bag of doritos and order him to eat no more than two.

2. Turn on a Hendrix tune and watch to see if the driver suddenly produces an invisible guitar

3. Wiggle fingers in front of the drivers face to see if it freaks him out

4. Ask the driver to walk a straight line. If he continues for 3 or 4 miles without looking back, I would say they have a case

Whatever you do, don't hand them your NBA trading card and tell them you're with the Blazers. That stuff won't fly in Washington.

SEV:

What if I say I'm with the Thunder? :)

DUI laws were not changed.

The main argument against legalization of pot is this whole issue of driving while impaired. Before legalization it was still illegal to drive under the influence of marijuana. So the law is the same. What do they do now to prosecute? The type of person who would drive impaired is already doing so. Sure, there will probably be a few more.

Isn't it kind of easy to smell...maybe an intensity of smell meter.

This problem shows why business climate is so important. The recent, lamented case of the demise of Hostess foods takes away an important indicator of marijuana use. A quick visual of a suspected impaired driver's car for Twinkie wrappers, or the flakes of pink coconut on the front of the driver's Willie Nelson concert shirt could have easily become probable cause. Perhaps the presence of Taco Bell wrappers will suffice.

It's just sad. Maybe a copy of Dr. Dre's The Chronic, or any of Snoop Lion (née Dogg) playing will become new reasons to suspect impairment. I know if I were a traffic cop and I smelled cheap strawberry incense, I'd be on heightened alert.

I know it's weak satire, but not everybody is Bill McDonald.

Maybe run the ad hoc statistics - blood-sample or test people after accidents, especially accidents with fatality.
My theory: You won't get many pot statistics. Buzzed pot smokers more often than alcoholic hot heads stay on the couch and joystick their adventures, instead of going hard driving, road raging like alcoholics, driving fatally too fast.

My other prediction: Legal pot now means businesses quit pre-employment drug testing and as a result, many hold-out job applicants with good talents and trained skills and moral decency are going to show up to work where, before, they would not stoop and degrade themselves suffering personal invasion in order to join a no-fun company of all fascists. At last, soon there may be young clerks at checkstands with smiles and good attitudes, and able to count change correctly, or even -- gadzooks! -- figure the total and the change when the power goes out or the computer goes down and the cash register don't work.

I expect to see the cops relaxing with a few puffs of the ol' peace pipe, too, either after-hours or on-duty, or both, and a lot less violence.

Some credible research report (I didn't follow the link, Yale source maybe?) released last week found legalizing weed reduced adolescent crimes over 20% in the first period sampled (a year?), reducing the spiked-high prevalence in prior fear-foment times. On the downside, all the fear dealers and gun sellers losing commerce are more likely to go postal, of course, being seen as jokes and laughingstocks in the increasingly larger public of their betters; similarly, military recruitment might plummet. It's all good.

I could easily be wrong here but the substance that the drug tests test for is a metabolite of THC. They do this because THC has too short of a half Life. A similar test is done for heroin because heroin has a half Life of only a few minutes but it's metabolite is present for a few days. Wouldn't we just need a test for THC and not its metabolite?

google "Drug Recognition Expert"

ha ha ha ha.........munch munch munch...........ha ha ha ha

A friend served on a jury regarding DUI for a medical MJ cardholder...they convicted based upon the evidence (including video)as the defendant failed a field sobriety test.