Pajuoja says tests for less-commonly used drugs are the least reliable. He expressed alarm that the tests give a false positive two thirds of the time for drugs including cannabis, cocaine and opiates.
Meanwhile, false positives for amphetamines – which are the most common drugs among drivers – occur nearly ten percent of the time.
Police are considering regulatory changes to prevent motorists from losing the right to drive if they falsely test positive for drugs. Pajuoja adds that officers should be aware of the limitations of the tests.
Several people who have unfairly lost the right to drive have filed complaints with the Parliamentary Ombudsman.