The RSA suggests the new rules will have a 'profound and positive impact' on road safety
Gardaí will be able to carry out roadside drug tests under new rules coming into effect from midnight.
The drug driving legislation - introduced under the Road Traffic Act 2016 - allows Gardaí to set up Mandatory Intoxicant Checkpoints (MIT) to test drivers for the presence of both alcohol and drugs.
Gardaí have traditionally tested drivers for potential drug intoxication through Roadside Impairment Testing - which included the likes of walking tests and 'finger-to-nose' tests.
A urine or blood sample then needs to be provided at a Garda station when a driver is arrested under suspicion of driving under the influence.
The new drug testing devices - which will serve as a further method of preliminary drug testing - will allow officers to test a sample of a driver's saliva for the presence of drugs such as cocaine, heroin, Valium and cannabis.
Anyone found to be over the legal threshold for cocaine, cannabis or heroin faces a minimum one-year disqualification from driving.
As well as disqualifications from driving, other potential drug driving penalties include prison terms of up to six months or fines of up to €5,000.
Road Safety Authority Chief Executive Moyagh Murdock said she has 'no doubt' that the new tests will have a 'profound and positive impact' on road safety.
She said: "Our own research shows that many drug drivers incorrectly believe that certain drugs make them better drivers and imagine themselves at low risk of collision.
"They also tend to overestimate their driving ability and show little understanding of how drugs affect their driving."
Professor Denis Cusack of the Medical Bureau for Road Safety, meanwhile, moved to allay concerns of any drivers taking prescription medication.
He explained: "Drivers with medical conditions should continue to take their prescribed medications in accordance with healthcare advice and medical fitness-to-drive guidelines.
"If you are taking prescription or over-the-counter medicines under the advice of your doctor or pharmacist, and so long as those medicines don’t impair your driving, you have nothing to be concerned about."
Assistant Commissioner Michael Finn added: "There will be 86 drug screening devices located in Garda stations nationally and 50 more available for use at the roadside. Over time up to 150 devices will be available for use at the roadside.
"While the test will take longer to conduct than the roadside test for alcohol, the test is easy to carry out and within minutes will tell if a driver has drugs in their system."