The UK government has announced that roadside drug analysers will be introduced during 2012 and that a new offence, driving with an illegal drug in your system, will be created. Around 750 000 people in the UK have driven under the influence of cannabis and 370 000 under the influence of Class A drugs, according to the UK's Institute of Advanced Motorists. Numbers in South Africa are uncertain but, given the easy access to cannabis, it's likely that the numbers will be high.We wonder if SA will follow the UK lead?The problem is that the UK has yet to set the limits of an illegal substance above which a driver is deemed to be unfit to drive. Unless drugalysers can provide proof of impairment in situations where a number of drugs and alcohol may have been consumed, their main role will be as detectors of the presence of illegal substances.IMPAIRMENT A KEY FACTORThe IAM, the UK’s largest independent road safety charity, says impairment testing should not be forgotten in the rush to provide a technological solution to the drug-driving issue. Chief executive Simon Best said: “Any new equipment that will allow police to make quick and accurate decisions at the roadside or at the police station on drivers who are impaired by drugs is great. In this way traffic officers can get back out on to the front line of roads policing, where their impact is greatest.“The introduction of a drugalyser-type test needs to be backed up by some measure of impairment. Without this, the test could simply catch those people who have used drugs at some point, but are not necessarily still impaired by them.“Impairment as the key factor is also essential in tackling drivers who may have used over the counter or prescription drugs, which while legal, can have an equal impact on driving ability as illegal ones."Anyone in the SA police or transport ministry listening?