Over here, they actually do a roadside drug test which is a saliva swab. It is testing for opiates, meth, amphetamines, etc. If positive, you are charged pending a lab screen test that will show if you are taking codral, etc (based on the trace make-up). We do the same thing in the Mining industry, but it is normally urine analysis - which is more accurate and the drugs are more visible for longer.
Would have thought that the requirement was to prove that you are impared and using something that was illegal - rather than charging you indiscriminately. What happenned to the Magna Carta - innocent until proven guilty?
I can understand doing the testing to create a deterent and to catch those putting others at risk - but common over the counter drugs - come on.