The ACT's peak drug body has renewed calls for greater awareness of drugged driving, after a jump in the number of motorists nabbed at roadside drug tests.
About one in six Canberra drivers failed random roadside drug tests in the three months to February, which left police concerned motorists hadn't understood the dangers of driving under the influence of drugs.
Police identified 82 drug-impaired drivers from 508 tests as they zeroed in on drunk and drugged motorists on the ACT's roads over summer.
Forty-eight drivers tested positive to drug driving in the same period last year.
Alcohol Tobacco and Other Drug Association ACT executive officer Carrie Fowlie said the results reinforced the organisation's view that better public education on the tests, similar to drink-driving campaigns, was overdue.
"We all want to be safe on our roads and no one wants impaired drivers on our roads," Ms Fowlie said.
"But Canberrans have the right to know what the law is and to have explicit information about how to stay safe on our roads.
"There needs to be general public education and targeted education among communities of drug users and should include an evaluation component.
"When people have the correct information, they're more likely to make safe choices."
ATODA has criticised the tests because of a lack of evidence they were effective in reducing serious crashes and improving road safety.
The ACT was the last Australian jurisdiction to introduce the controversial random roadside drug tests, in 2011.
Under previous legislation, police had to suspect a driver was under the influence of drugs before they could test them.
The mouth swabs can detect only cannabis, speed, and ice or ecstasy, and any positive result, after laboratory tests, triggers an offence.
An independent evaluation of the ACT's roadside drug test methods last year showed 35 per cent of Canberrans didn't know about the program.
Ms Fowlie said an awareness campaign must communicate the dangers of driving after using any of the illicit drug types tested, the drug-driving offences and penalties and how they were enforced, and how motorists could avoid committing a drug-driving offence.
There also needed to be information about how long the drugs could be expected to remain in users' systems.
Drink-driving counter-measures had been effective because there had been a sufficient number of penalties imposed over the years, which acted as a deterrent, accompanied by consistent policies and legislation, she said.
Alcohol limits for drivers had been set and communicated clearly through social marketing campaigns, which had "enabled a culture where drink-driving is no longer acceptable in the community", she said.
But said similar measures hadn't been replicated for roadside drug tests and the method used had significant limitations, which could undermine its effectiveness, she said.
Chief among her concerns were that the method detected only three drug types and tested only for the presence of an illegal substance, rather than impairment.
"We need to focus on the purpose of the legislation. This is about road safety, it's not about empowering police to catch out drug users.
"The population data tells us that people aren't using drugs more. I think what [the latest results] indicate is that police are using intelligence-based roadside drug testing, not random drug testing."
The ACT Justice and Community Safety Directorate and police are developing a public awareness campaign to educate motorists about the dangers of drug driving.
It's set to launch in the next financial year.
A directorate spokeswoman said the campaign would promote awareness of roadside drug-testing operations, as well as details about penalties and potential consequences.
Australian National University academic David McDonald questioned last year the effectiveness of random roadside drug tests and made a similar call for better education - a suggestion that was backed by the ACT Council for Civil Liberties.