Pubdate: Sat, 24 Mar 2001 Source: Essex Chronicle Copyright: 2001, Quicksilver Media Contact: 43-44 North Hill, Colchester, Essex CO1 1TZ Fax: 01206 508295 Website: http://www.thisisessex.co.uk URINE SCREENING TESTS UNSAFE Sir: THE case for urine screening tests for illicit drug driving, (Chronicle Town edition March 16): although well intentioned, is fundamentally flawed as drug-screening tests are unsafe. Unlike the breathalyser which tests can accurately detect alcohol impairment, drug tests fail on their own terms: Their greatest shortcoming is their inability to determine impairment at the time the test was taken. Therefore, any standard levels of presumptive impairment become meaningless in practical application. The possible variations involved in drug screening tests render the task of the general acceptance of a presumptive level of impairment for cannabis practically impossible. A positive drug test standing alone, is not precise enough to supply the formal proof needed for prosecutions, such as driving under the influence of drugs. Don Barnard Legalise Cannabis Alliance http://www.lca-uk.org - --- MAP posted-by: Josh Sutcliffe