Roadside drug tests are becoming increasingly common in Australia. The tests usually require the driver to submit to an officer’s collection of a saliva sample. A simple test checks the sample for the presence of cannabis, methamphetamine, or Ecstasy (MDMA).
No scientific evidence has determined whether a positive test result means a driver is under the influence of the drug. In most cases, drugs can be detected in a person’s saliva long after the person is no longer affected by the drug.
To make the job of police officers easier, state legislatures in Australia have made it illegal to drive with any detectable amount of the drug in the driver’s body. That places drivers at risk of being prosecuted, and losing their driving privileges, even if they are perfectly sober and driving responsibly.
In 2015, one out of every seven drivers in NSW who submitted to a roadside drug test “failed” the test. By comparison, only one of every 236 drivers in NSW test “over the limit” for alcohol use.
There are two reasons that so many more drivers fail the drug test. First, there is no “limit” for drugs as there is for alcohol. A driver who had a glass of wine before driving might have a 0.02% test result and will pass the test. On the other hand, a driver who takes a puff of cannabis hours before driving will fail the test, even if the amount of cannabis in the driver’s blood is negligible, as long as it can be detected.
Second, alcohol leaves a driver’s blood within hours after taking the last drink. A driver who consumes a large quantity of alcohol will have no alcohol in his blood 24 hours later. A driver who consumes even a modest amount of marijuana will still have a positive test result the next day, and might even have a positive test for several days.
A driver who smokes marijuana several times a week might have a positive test result for more than a month. The chemicals that show up in the tests for cannabis are stored in the body’s fat cells. They are slowly released into the body over time, resulting in positive tests even though they no longer affect the ability to drive.
Drivers should never assume that a roadside drug test is accurate. In many cases, a confirming test will cast doubt on the validity of the roadside test. That doubt can be used to challenge the evidence and, in many cases, avoid a conviction.
Given the general understanding that roadside drug tests are unfair, some judges are inclined to give the driver a break when there is no evidence in impairment or bad driving. A lawyer may be able to help a driver minimize or avoid the consequences of a “failed” roadside drug test.
Disclaimer : This article is just a summary of the subject matter being discussed and should not be regarded as a comprehensive legal advice for you to defend yourself alone. If you are charged with criminal offences, it is recommended that you seek legal assistance from criminal lawyers.