DANGEROUS ALCOHOL

THE article ``Cannabis `not risky' '' (The Advertiser, 31/10/01) does
not accurately reflect my views on cannabis and the risk of being
responsible for a road accident.

There is no doubt that marijuana adversely affects driver performance
but it has yet to be shown statistically that it increases the risk of
causing a crash.

There is some evidence that this may be because of an effect of
marijuana on driver behaviour. Whatever the reason for the lack of a
demonstrated statistical association, marijuana may increase the risk
of causing a crash for some drivers in some circumstances,
particularly at very high doses of the drug.

While we should be concerned about the effect of any drug on road
safety, the most dangerous drug, by far, is alcohol.

(Professor) JACK McLEAN

Director, Road Accident Research Unit, Adelaide University