Why Is It So Hard To Test Whether Drivers Are Stoned?

[GregS]

Is there really a field sobriety test that can conclusively indicate intoxication? We read the article explaining how that swabs or breath analysis is inadequate to determine it. Short of a blood draw, which requires a warrant, probable cause must be established. I have had several, umm, pleasant conversations on the roadside with officers of the law who had no clue.