ROADSIDE screening devices capable of detecting "drug-drivers" are expected to be introduced within two years, The Scotsman has learned.
The UK government is set to give the green light by January for the development of new equipment to catch people who get behind the wheel after taking illegal drugs.
Home Office sources say manufacturers have already been told about the likely requirements of the kits, which will look for drugs such as heroin, cannabis, Ecstasy, cocaine and amphetamines.
It is anticipated that a pilot scheme will be launched early next year, after which they will be made available to police forces across the country.
Senior officers are anxious to see the introduction of a screening device to replace the current method of testing, which involves putting drivers through a series of physical tests to determine whether they are impaired by drugs.
A study by Glasgow University found that more than a third of motorists who drive after taking illegal drugs nevertheless pass the roadside sobriety tests. Even some with heroin in their system managed to beat the test.
The Home Office "type approval" rules are expected to be issued later this year, identifying which substances have to be picked up and the levels at which a positive reading will be triggered.
A source said the department's scientific development branch was expected to release its specification "within the next few months", after which pilot schemes would be run in selected police forces.
"All being well, we would look for them to be introduced on Britain's roads within two years," the source said.
It is understood the list of drugs to be screened by the new equipment is likely to include opiates, cocaine, cannabis, amphetamine, methamphetamine ( Ecstasy ), methadone and benzodiazepan.
Assistant Chief Constable Ian Learmonth, of the Association of Chief Police Officers in Scotland, said: "Whether people are fit to drive and if there is anything impairing them when they are behind the wheel is something we have to be able to identify.
"If somebody can produce a piece of equipment that allows us to undertake roadside screening for drugs, which would give us a clear indication whether drivers are impaired, that would assist us greatly and we would welcome that."
Oxfordshire-based Cozart developed the Rapiscan drug-screening kit, already used by the Home Office for testing offenders. It involves taking a swab from the subject's mouth, which is dispensed on to cartridges. Each cartridge is inserted into a handheld reading device, which gives a positive or negative result for a particular drug within five minutes.
It is thought this device will be one of those tested for use by traffic police.
A spokeswoman for the firm said: "Police have told us they are happy with the devices and want to use them for detecting drug-drivers. The problem with the roadside impairment tests is that they are not precise and suspects have to be taken away for a blood test to determine the level of drugs in their system. Our device gives police an answer within minutes."
Research commissioned by the Scottish Executive published last week found the absence of a scientific roadside test encourages people to drive after taking drugs, and called for police to be equipped with a more reliable test. Experts estimate up to 11 per cent of Scots have driven after taking illegal drugs.
The survey found 72 per cent of respondents felt it was unlikely that someone driving under the influence of drugs would be caught. Just over half ( 55 per cent ) of drug-drivers were not concerned about being caught.