Evaluation of a Prototype Driver Impairment Device in Volunteers: A Double Blind Placebo Controlled Crossover Study with Alcohol

Background Driving performance is easily disrupted as a direct consequence of the use of alcohol, licit and illicit drugs. Epidemiological research suggests that a blood alcohol level of 80mg/100ml (the UK legal limit) is associated with an approximate doubling of the risk of a driver becoming involved in a collision. This legal BAC limit is used as a reference point to indicate the impaired and non-impaired performance of a driver. For many years alcohol has been the drug of greatest concern since it is one of the most commonly used psychoactive substances and the most frequently recognised cause of drug induced driver impairment However, psychoactive drugs both medicinal and illegal can have an equally impairing effect on driving performance. Psychoactive substances can cause impairment of attention, information processing, memory, and divided attention, the disruption of which will have a direct consequence on an individual’s ability to drive. Sedative drugs have been shown to impair car handling ability and other drugs especially tricyclic antidepressants and benzodiazepines have been shown to play an important role in accident causality. In addition, research has shown antihistamines to cause driving related impairment . These drugs continue to be heavily prescribed to patients who are likely to drive, with some impairing antihistamines available over the counter without prescription. Research relating to illegal drugs and their ability to impair driving is also prevalent. Cannabis, heroin, methadone and ecstasy all have detrimental effects on an individuals ability to attend to the complexities of driving 9, 10 & . Epidemiological data of fatal accident victims showed that there was a presence of illegal drugs in 18% of cases and of medicinal drugs in 6% of cases and whilst there is an annual average of 75000 convictions for driving above the prescribed legal limit of alcohol in England and Wales, there are fewer than 2000 convictions for driving whilst unfit through drink or drugs. There is not at present any objective test available in line with the breathalyser that can be used at the roadside to determine impairment due to drugs, whether impairment is brought about through prescription medication, OTC medication or illegal substances.