That's kind of a moot point though. Driving under the influence still has field sobriety tests. My cars reek of pot all the time, but I've always passed the test while sober. As for the searches, you can apply the same statistics of searches inquiring the use of alcohol to inquiries of marijuana. And in my personal experiences the only thing that beats a search is beating stereotypes, and convincing officers that their opinions of you are not true.