Three-quarters of 'sober' drivers were on drugs
Three-quarters of motorists who passed a roadside breath test but then gave blood or urine samples were found to have taken illegal drugs.
The drivers were tested because they were believed to be under the influence of either drugs or alcohol. But despite passing the breath test, gardai still believed they were impaired and asked them to provide a blood or urine sample which later tested positive for drugs.
New figures show that some drivers had as many as seven drugs in their system when behind the wheel, with cannabis and tranquillisers the most commonly abused narcotics.
Professor Denis Cusack, director of the Medical Bureau of Road Safety (MBRS) that analyses blood and urine samples for drugs and alcohol on behalf of the gardai, said the problem of drug driving was getting worse, but that there was a low rate of prosecutions.
Prof Cusack said 865 samples tested positive for drugs last year, but just 421 people were prosecuted.
Since 2007, some 5,835 positive tests were found but just 2,912 drivers were taken to court.
Gardai will begin carrying out roadside impairment tests from next summer that allow them to determine if someone is under the influence of drugs.
Some 3,000 gardai have been trained to perform the tests, which include examining the driver's eyes, especially the size of the pupils; asking the motorist to stand with their eyes closed to see if they start swaying; and asking the suspect to touch their nose with a finger, with eyes open and then eyes closed.
Gardai can ask any motorist to take a breath test, and provide a blood or urine sample, if they believe they are under the influence of drugs or alcohol.
Prof Cusack said: "Under current road traffic law, the gardai must be satisfied that a driver is under the influence to such an extent as to be incapable of having proper control of a vehicle. This means that the garda has to prove driver impairment to the satisfaction of the court and this can cause difficulties in successfully prosecuting such offences. These new provisions will assist gardai in forming the opinion that a driver is impaired due to drug intoxicants."
MBRS research shows drug-driving is increasing, with cannabis, tranquillisers, cocaine, ecstasy, opiates and amphetamines the most commonly found drugs.
The report also shows that half of all drivers who passed an alcohol test had taken cannabis, with 40pc taking tranquillisers. More than 40pc of drivers had taken two or more drugs. A small minority were found with seven drugs in their system.
Senior garda sources said the new roadside impairment tests would help increase the number of people being prosecuted.
"The big problem with the drugs is you have to show the driver is incapacitated," one said. "If we have a checkpoint, and the motorist is obviously under the influence of something, they might be under the limit for alcohol.
"When we go to produce our evidence in court, how do we prove they were incapable of driving?"