drug-driving-expert-panel-report

(1) A person who, when driving or attempting to drive a mechanically propelled
vehicle on a road or other public place, is unfit to drive through drink or drugs
is guilty of an offence.
Therefore the Panel has not sought to define and measure or proportion a
concentration of a drug in a person’s body to a certain degree of impairment. There are
two main reasons for this decision. Firstly, there is no universal agreement on how to
objectively measure impairment for psychoactive drugs and driving. Secondly, the Panel
considered that defining impairment for several different classes of drugs would prove
too complicated and not sufficiently robust to inform drug‐driving legislation, if such a
task could be completed at all. Psychoactive drugs impair individuals in different ways,
for instance stimulants by increasing alertness and confidence, depressants by
decreasing responsiveness, and hallucinogens affect a person's perceptions, sensations
and self‐awareness. The North Report set out the diverse effects of drugs in term of
their effects on the skills required for safe driving and emphasised the fact that drugs
such as stimulants which may have some performance enhancing effects, for example
by improving reaction times, often also have adverse effect such as reducing critical
judgement, increasing impulsiveness or increasing error rates.
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