While cannabis is far less impairing than alcohol, no one wants seriously impaired drivers on the road. When the legal basis for their use is finally established, the facts about marijuana's impairment of driving will be established with results not to the liking of prohibitionists. A breath test unit to screen drivers for cannabis has been developed to prototype stage by doctors Ron Parsons and Zenon Mejglo, research chemists at the University of Tasmania in Hobart. Dr Parsons has been working on the project for about 20 years and was joined by Dr Mejglo in 1992. At present the police only have one instrument, the breathalyser for alcohol.
People smoke cannabis and blow nothing on the breathalyser.
The police know their driving ability is impaired, but they can't do anything about it. They've got them then and they have to have a blood test because breath analysis is only a screening test. Dr Parsons said police in Tasmania could already order an immediate blood test if they suspected a driver was under the influence of drugs. Blood tests must be performed within two hours after smoking cannabis to be effective. If you go soft on cannabis the police have no check on people driving under its influence.