Paul Enos, CEO of the Nevada Trucking Association, a state where recreational marijuana use is legal, said tests that capture weeks-old use force people out of the industry who are not necessarily a danger on the roads. Another complication: The only accepted roadside tests for marijuana use can produce positive results more than a month after the person smoked or consumed it, unlike commonly used breathalyzer tests for alcohol impairment, which give a snapshot of the moment the test was conducted.
