UK cops are persisting in introducing a series of roadside tests for stoned drivers, despite a study released by the UK Transport Research Laboratory in August 2000, which found that pot-smoking has a minimal if not beneficial effect on driving performance.
The government-funded study was launched under pressure from anti-drug and driving groups, and was an embarassment to the British Ministers who had expected it to support their anti-stoned-driving campaigns.
The British study confirmed the results of a wide variety of research into stoned driving from around the world:
A 1983 study by the US National Highway Transportation Safety Administration (NHTSA) used stoned drivers on simulators, and concluded that the only statistically significant effect associated with marijuana use was slower driving.
A comprehensive 1992 study by the NHTSA found that marijuana is rarely involved in driving accidents, except when combined with alcohol. It concluded that “the THC-only drivers had an [accident]responsibility rate below that of the drug free driversS While the difference was not statistically significant, there was no indication that cannabis by itself was a cause of fatal crashes.” This study was buried for six years and not released until 1998.
Another NHTSA study performed in 1993 dosed Dutch drivers with THC and tested them on real Dutch roads. It concluded that “THC’s adverse effects on driving performance appear relatively small.”
A massive 1998 study by the University of Adelaide and Transport South Australia analyzed blood samples from 2,500 accidents, and found that drivers with cannabis in their system were actually slightly less likely to cause accidents than those without.
A University of Toronto study released in March 1999 found that moderate pot users typically refrained from passing cars and drove at a more consistent speed than non-users.
An important consideration when considering the effects of cannabis and driving is whether the smoker is an experienced user. Novice tokers typically experience more difficulty driving than regular users.
The British study also found that tiredness caused 10% of all fatal accidents, compared with 6% for alcohol.
Despite these many conclusive results, UK cops are promoting their new roadside tests for “drugged drivers.”
Drivers being tested for stonedness must estimate the passage of 30 seconds, walk a straight line while watching their feet, have their pupils examined for dilation or constriction, and finally be forced to stand on one leg with their head tilted back, eyes shut, arms extended, and touch their nose three times with each hand. (This last one is not easy even for the very sober – try it.) Perhaps most importantly, officers are instructed to pay attention for “herb-like smells” during the tests.
Those who fail any aspect of the test must provide a blood sample for drug testing. Failing or refusing the blood sample brings a conviction for “drugged driving.”
British police bragged they would be able to test 20,000 drivers each year, leading to a 10-fold increase in arrests and charges.
* * *
Media stories on the UK driving study:
UK Times: Cannabis May Make You A Safer Driver www.mapinc.org/newscc/v00/n1161/a02.html
Ottawa Citizen: Researchers Say Pot Makes Drivers Safer www.mapinc.org/newscc/v00/n1209/a07.html
Media stories on the UK drugged driving roadside test:
Reuters: British Police Plan New Drug Tests For Drivers www.mapinc.org/newscc/v00/n1105/a12.html
Irish Independent: Drug Test Drivers To Walk The Line www.mapinc.org/newscc/v00/n1108/a04.html
1983 National Highway Transportation Safety Administration study: Stein, AC et al., A Simulator Study of the Combined Effects of Alcohol and Marijuana on Driving Behavior-Phase II, Washington DC: Department of Transportation (1983)
1992 National Highway Transportation Safety Administration study: The Incidence and Role of Drugs in Fatally Injured Drivers, by K.W. Terhune, et al. of the Calspan Corp. Accident Research Group in Buffalo, NY (Report # DOT-HS-808-065) www.drugsense.org/tfy/nhtsa1.htm
1993 National Highway Transportation Safety Administration study: Marijuana and actual Driving Performance, By Hindrik WJ Robbe and James F O’Hanlon. Institute for Human Psychopharmacology, University of Limburg www.druglibrary.org/schaffer/hemp/general/mjdrive.htm