ABSTRACT
The basis of such laws is quite simple: the faster you are travelling, the greater the risk of loss of control and collision, and the greater the level of injury. If you are intoxicated from some substance, the more intoxicated you are, the greater
the chance of collision. Legal limits are established for acceptable levels of alcohol in blood, breath or urine. Currently in the UK, the maximum legal permissible blood alcohol concentration is 80 mg alcohol/100mL of blood, although this is hopefully going to be reduced in the future to 50 mg alcohol/100mL of blood to bring it (and the equivalent breath and urine levels) into line with the majority of Europe. The assessment of the effects of drugs and alcohol on ability to drive (in addition to a simple legal limit) is very important because of the variable individual response to the effects of alcohol and other substances. In many cases, ‘driving under the influence’ may be confirmed by the ability, or failure, to pass standardized tests of sobriety, or by medical examination to determine whether the ability to drive may be impaired, following preliminary impairment tests undertaken by police personnel.
