Following some success in random alcohol breath testing, the focus is shifting to illegal drugs, writes Mark Rodden

While random breath testing has helped authorities clamp down on drink driving, it has also hinted at the extent of a growing drug-driving problem in Ireland. Recent research has suggested it is a significant and increasing crime, and authorities around the world are still discussing the best way to deal with it.

In Ireland, a nationwide study by the Medical Bureau of Road Safety (MBRS) in 2000 and 2001 found that one-sixth of all drivers tested had drugs in their system, while a third of 1,000 samples that were under the limit for alcohol tested positive for drugs. Some 68 per cent of sampled drivers with essentially zero levels of alcohol tested positive for one or more drugs.

The bureau receives blood and urine samples for analysis when gardaí suspect someone is driving under the influence of a drug, when they find someone under the level for alcohol, or when it is requested from someone who has been involved in a traffic accident or committed an offence. The MBRS are due to analyse about 1,000 samples taken in 2006 for drugs, having found that about six in 10 of the 747 specimens they analysed for drugs in 2005 tested positive.

The MBRS currently tests for seven drug types: cannabinoids (such as cannabis), benzodiazepines (tranquilisers), amphetamines and methamphetamines (such as speed and ecstasy), cocaine, methadone and opiates.

The most common drug found is cannabis, followed by benzodiazepines, but Prof Denis Cusack, director of the MBRS, says that new trends are appearing that reflect drug use in society. "About six years ago, cocaine would have been at the very bottom, but now it's around joint third," he says.

Section 10 of the Road Traffic Act states that it is illegal for people to drive under the influence of an intoxicant - either drink or drugs - while in a public place. There is no breakdown of statistics for the number of people prosecuted for drug driving, but Garda figures show that there were 109 suspected incidents or detections of drug driving in 2005 and 113 in 2006.

Sgt Pat Curran of the Dublin Regional Traffic Division has noticed an increase in the level of drug driving, and last month his team arrested five people in one weekend in the west Dublin area. "It's very prevalent and we're well aware of it," he says. "It's as bad as drink driving, if not worse - especially if it's a combination of drink and drugs."

In Ireland, as in most countries, there is currently no roadside test for drug driving. Some European countries have adopted a zero-tolerance approach to illicit drugs, meaning the presence of a drug in someone's system when they are driving is enough evidence for prosecution. Here, however, it is necessary to prove both that there was an intoxicant in the system at the time of driving and that driving was impaired by its presence.

Prof Cusack believes that a zero-tolerance strategy would help the Garda because less evidence would be required to secure a conviction, but that, in practice, it might not make too much difference. "Even in countries that do have zero tolerance, in order to come to the attention of the authorities you would still have to show some signs of impaired driving," he says.

UNLIKE ALCOHOL, THERE is no limit set for the level of drugs allowed in someone's system while driving, so Sgt Curran believes gardaí are adopting a zero-tolerance approach anyway. "If we find that a blood or urine sample is under the limit for alcohol, it goes for a drug test," he says. "If the drugs are there, we can prosecute."

Sgt Curran also believes the misuse of prescription drugs is an emerging issue and says the Garda have successfully prosecuted a number of people whose driving was impaired because they were drinking while taking prescribed medicines.

One country where a roadside testing device has been introduced is Australia. In December 2004, the state of Victoria introduced a roadside test using saliva swabs. The swabs are tested for cannabis, speed and ecstasy, and a Victoria police spokeswoman said that during a trial period one in 46 motorists tested positive for drug driving, which was over four times the drink-driving ratio.

According to Sgt Curran, a number of similar roadside devices are being tested by the Garda. One Irish technology company, Cork-based Biosensia, announced earlier this month that it is creating a hand-held roadside testing device which, using a swab sample, will test for between three and seven drugs. Prof Gabriel Crean, chief executive of Biosensia, says it will be tested later this year and he hopes it will be in use by late 2008.

Prof Cusack of the MBRS says the Biosensia development is encouraging but that it would have to pass rigorous forensic tests before its use could be considered.

He also points out that an international study found that nine roadside testing devices it studied were unsuitable. The difficulties in developing a reliable test were highlighted in Australia, where the first person to test positive after a roadside drug test was later cleared by laboratory tests. The initial test result was much publicised, and last year a judge ruled that the driver could pursue a defamation case against Victoria police. However, Victorian police have since modified the way they test and no one who tests positive is charged before the results of the laboratory analysis.

A more likely development in Ireland in the near future could be the introduction of the Field Impairment Test (FIT), which is used in the UK, where 18 per cent of drivers who died on the roads between 1996 and 2000 had illegal drugs in their system). An adaptation of the Field Sobriety Test, it sees drivers being asked to perform a number of tasks that assist police in deciding whether to arrest them.

In Northern Ireland, almost a quarter of drivers killed between 2001 and 2003 and whose blood was analysed had consumed an "impairing drug", which refers to both illegal and prescribed medicines. The FIT was introduced there in 2002, and the PSNI says there were 131 drug-driving detections in 2005.

Prof Cusack travelled with the Garda Traffic Corps to see the PSNI in training and believes this more formalised procedure would give gardaí a better chance of detecting possible drug drivers.

However, a spokeswoman for the RAC Foundation, which has campaigned on the drug-driving issue in the UK, says the test is subjective, and that a study by Glasgow University last year found that one third of drivers under the influence of a range of drugs were able to pass it.

In the absence of a roadside test, Prof Cusack says that most countries are going through the same discussion on how best to tackle drug driving. "It's about safe driving, and if someone has drugs in their system then they're not as safe as they should be," he says.

But with drug driving most common among males aged under 25, it seems that education and awareness will be just as important as enforcement.