Saliva driving drug test "not feasible"

A leading Dutch research centre on drugs and addiction says a total ban on drugs while driving is not feasible. The warning from the Trimbos Institute, which advises the cabinet, comes in response to a call, launched on Saturday by the Council of Police Commissioners, for zero-tolerance with help of a saliva test. They believe a strict policy will help in reducing overall traffic fatalities.

According to Trimbos Institute researcher Daan van der Gouwe saliva testing is flawed in a number of ways. It does not indicate when and which quantities of the drug were consumed. The institute claims the test does not detect the use of cannabis and sleeping pills. False positive results are not uncommon. For instance, the test continues to detect cocaine traces days after the drug stops affecting the body. Traces of cannabis are known to possibly remain in the blood up to two weeks after use.
Numerous studies have shown that unlike tiredness, medication and alcohol, marijuana does not play a significant role in impairment of motor skills. A 2004 study conducted by the Dutch Institute for Road Safety Research (SWOV) concluded that ‘No increased risk for road trauma was found for drivers exposed to cannabis.’

The institute advises to wait with the introduction of a saliva test until further research has been completed.