KEY POINTS:
CANBERRA - It doesn't pay to take the high road in Australia any more.
The conviction yesterday of a 26-year-old Sydney man for driving under the influence of cannabis - the first under new roadside drug testing laws in New South Wales - has signalled that having a
puff or popping a pill before getting behind the wheel is in the same sin bin as drink-driving in the lucky country.
New South Wales has followed Victoria, Tasmania and South Australia in introducing saliva tests to detect the presence of cannabis, ecstasy and methamphetamines with such street names as speed, ice and crystal meth.
Queensland, when it has refined the technology and put its laws into place, will add cocaine and heroin to the testing list.
And Western Australia intends putting drug test buses on the road when its roadside testing laws come into force in July.
Despite early concerns over accuracy and civil rights, saliva tests on the side of the nation's roads are now a fact of life across the continent.
The first state to move was Victoria, with world-beating legislation that came into effect in December 2004.
It was pushed by studies that found that 31 per cent of drivers killed on the state's roads the previous year tested positive to drugs other than alcohol.
Researchers found that drivers who had recently smoked cannabis or taken methamphetamines were at the same risk of crashing as those with a blood alcohol content of 0.5.
Similar grim findings elsewhere prompted other states to follow suit.
In Tasmania, illicit drugs were found in the blood of almost a quarter of the drivers killed in motor accidents on the island between 1999 and 2003.
Early Tasmanian tests found that one in 10 drivers providing a saliva sample had returned positive results.
In South Australia, where roadside testing came into force last July, 23 per cent of drivers killed between 2003 and 2005 had cannabis, speed or ecstasy - or a combination - in their blood.
Further research estimated that 17 per cent of West Australian drivers aged 20 to 29 had been behind the wheel while under the influence of drugs.
Key targets are young men and truck drivers who use amphetamines to stay awake.
Studies have shown that cannabis lowers alertness, concentration, co-ordination, reaction time and the ability to judge distances and react to road signs and sounds.
Its active ingredient, THC, can be detected by saliva testing up to five hours after consumption.
Authorities have also attacked the myth that amphetamines keep sleepy eyes open.
"In reality, they greatly increase the severity of sleep rebound crashes," the South Australian Government warns.
"Microsleeps and crashes caused by fatigue impairment are often the result of drivers using stimulants."
The third roadside testing target, ecstasy, distorts perception, thinking and memory, impairs tracking ability, slows reactions and causes disorientation of time and place.
Saliva testing can detect both methamphetamines and ecstasy up to 24 hours after use.
Laws in all states allow trained police to randomly test for drugs at any time.
The results of an initial saliva test using an absorbent swab take about five minutes.
If it is positive the driver must provide a second sample for further analysis, with the result known within 30 minutes.
This must be confirmed later by laboratory tests.