An Irish judge last Friday threw out drugged driving charges against a young driver, saying that a positive result for marijuana in his urine sample was not specific enough to allow him to conclude that the driver was indeed impaired. Judge Kevin Kilrane of the Ballyshannon District Court in Donegal also criticized the Road Safety Medical Bureau for failing to test for the level of drug intoxication in its drug tests.

Peter Gillen was pulled over shortly after 4:00am for driving erratically, and Garda Officer Sean Flynn described him as "very shocked, unsteady, and very agitated" upon being stopped. Gillen tested negative on a breath test for alcohol, but Flynn arrested him on suspicion of drugged driving, and a urine sample Gillen provided soon after came up positive for marijuana.

That wasn't enough for Judge Kilrane to find Gillen guilty of drugged driving, which carries a harsh penalty of an automatic four-year loss of one's drivers' license. The mere presence of marijuana in Gillen's system did not show he was impaired, the judge said.

"The defendant could have been stoned out of his mind or he might have had a trace element only," Kilrane said. "At best, all you have is suspicion, and suspicion is not enough." The evidence was "too thin" to convict he said, as he dismissed the charge.

Kilrane scolded the Road Safety Medical Bureau for only testing for the presence of marijuana and not quantifying the amount present. "It is not the fault of the gardaí," he said. "It is the fault of the bureau that does not give a concentration of drugs."

US states that have "zero tolerance" drugged driving laws operate on the same standard criticized by the Irish jurist. In such jurisdictions, the mere presence of marijuana or its metabolites is sufficient to garner a conviction, without the need to show actual impairment.