Development and present status of impaired driving legislation in the United Kingdom.

This article traces the development and present status of legislation pertaining to driving under the influence of alcohol (DUI) and other drugs (DUID) in the United Kingdom (UK). The Road Safety Act of 1967 represented a paradigm shift in the way that traffic offenders were prosecuted for driving after consumption of alcohol. This new legislation defined punishable concentrations of alcohol (ethanol) in samples of the driver's blood (80 mg%) or urine (107 mg%). The creation of these statutory concentration limits meant that it was no longer necessary to prove that a suspect was under the influence or impaired by alcohol at the time of driving. Also in 1967, a police officer in uniform was permitted to administer a roadside breath alcohol screening test to help make a decision whether a suspect should be arrested for further investigation. In 1983, the British government introduced a statutory breath alcohol concentration limit of 35 μg/100 mL and evidential quality breath analyzers were approved for use by the police as an alternative to sampling blood or urine for analysis. Evidence of driving under the influence of drugs other than alcohol depended on the results of a clinical examination and questionnaire done by a police surgeon. This was supported by evidence presented by the arresting police officers or other witnesses. In 2015, a radical change occurred in the legislation pertaining to drug-impaired driving where instead of relying on clinical evidence of impairment, concentration limits in blood for 17 psychoactive substances were defined by statute. These consisted of eight commonly encountered recreational drugs of abuse and nine prescription medications (opiates and benzodiazepines), all classified as controlled substances.