Saliva test for cannabis could someday help identify impaired drivers
(PHYSorg.com Chemistry)

In the U.S., those who consume alcohol and drive are often subjected to roadside stops, breathalyzer tests and stiff penalties if their blood alcohol content exceeds certain limits. Currently, no such test exists for cannabis intoxication, although the substance is known to impair driving, among other activities. Scientists now report that they are one step closer to a convenient saliva test for measuring cannabis levels at roadside stops.