In an effort to make money in the great police budget bonanza we call the "War on Drugs," police have created a certification where they can just look at you and determine what drug you are on. Apparently this is needed since scientific test like urine and blood samples "come back wrong all the time." The is in Cobb County GA (which isn't surprising.)
http://www.11alive.com/news/investigations/the-drug-whisperer/437061710
http://www.11alive.com/news/investigations/the-drug-whisperer/437061710