This from the National Documentation Centre on Drug Use website (Ireland) (http://www.ndc.hrb.ie/directory/news_detail.php?cat_id=&news_id=2944&pointer=0):
True extent of drug driving is underestimated, says expert
(Source:'Drug driving test needed': Irish Times – Motors p. 1, 14 Jun 2006)
The head of the Medical Bureau of Road Safety (MBRS), Prof Denis Cusack, has warned that the extent of drug driving in Ireland is significantly underestimated.
The MBRS tested some 750 drivers for traces of drugs in 2005; 1,460 drivers were tested for drink driving. ‘Worldwide, there is still no single satisfactory roadside instrument that would cover a sufficient number of drugs in relation to one type of body fluid’, said Prof Cusack. He added that the MBRS is in discussion with the Road Traffic Corps about training gardaí to recognise symptoms of drug intoxication in drivers. In Sweden, where police are given this kind of training, 7,400 people were charged with drug driving last year – about half the number that were charged with drink driving (15,700). Commenting on the evidence from Sweden, Prof Cusack said he believed that the difference in detection rates between Ireland and Scandinavia reflected differences in enforcement, rather than different levels of drug misuse.
It is not routine in Ireland to test a motorist for drugs when he has already been found to be over the alcohol limit. Prof Cusack said that two-thirds of drivers who tested positive for one or more drugs had essentially zero levels of alcohol in their systems, suggesting that measures to combat drink driving would not work against drugs.