Changes to drink and drug driving laws will result in thousands of people losing their licences and will fail to improve road safety, a NSW MP has said.
Laws brought in by the NSW government mean from May 20 drink driving offenders - no matter if they are first-time low, special or novice range - will receive a three-month licence suspension.
Offenders who drive with the presence of illicit drugs will also receive a three-month licence suspension if the offence is confirmed by laboratory analysis.
"Turning up to see a magistrate, being referred to a safe driving program, we know that can have an impact on recidivism, but that has been taken out of the system," David Shoebridge, NSW Greens spokesperson for justice and long-standing critic of drug driving laws, said.
"We are going to see thousands of people lose their licences, we will see a reduction in police prosecution costs and our roads won't be any safer - and surely the ultimate test should be road safety.
"This will produce arbitrary, unfair outcomes where people will be losing their licences largely due to trace amounts of cannabis in their system, when if their case was heard by a magistrate they might be given a second chance."
When people living in regional areas in particular lost their licence, he said, this could lead to a drastic loss of independence, possible loss of livelihood, being unable to maintain family and social connections and, if they lived far away from a town centre, not even being able to shop for food and supplies.
Under the changes offenders will also receive a $561 fine, but Mr Shoebridge said this was a "one size fits all" fine whether they were on a government pension, a minimum wage worker or an investment banker, so would have a drastic impact on people on a lower income.
He said a major problem with the state's drug driving laws was that police tested for presence of drugs, not impairment.
"We've seen many occasions where someone lost their licence because they smoked pot a week before they got behind a wheel of a car and it was found they had a trace of residual cannabis," he said.
"Meanwhile, people with highly-intoxicating levels of prescription medications are being waved through at these rest stops, namely benzodiazepines and other prescription drugs."
Mr Shoebridge said crash data from Australia and overseas showed benzodiazepines were one of the most significant drugs contributing to road trauma, other than alcohol, and were significantly higher than others such as ecstasy.
He said other jurisdictions around the world tested for impairment by matching concentration levels with crash trauma studies to work out the what concentrations were that impaired driving ability and called for a parliamentary inquiry into road safety, "rather than an unthinking extension of the war on drugs".