The Chair of the NSW State Committee of the Royal Australasian College of Surgeons (RACS), Dr Danette Wright, and the RACS NSW State Trauma Committee Chair, Dr Vikram Puttaswamy, said the changes weaken enforcement of a known cause of driver impairment while relying on a threshold that science cannot validate.
“Every week, surgeons across NSW operate on people whose lives have been changed in an instant by a crash,” Dr Puttaswamy said.
“Road trauma is largely preventable, and any change to impairment laws has to be judged against that reality. On the current evidence, these changes do not pass that test.”
Under the proposed framework, registered medicinal cannabis users who test positive at the roadside but fall below a maximum THC threshold on laboratory testing will no longer be automatically penalised. Those above the threshold would receive two warnings before a third detection within two years attracts a $704 fine and a three-month licence suspension.
The Committee acknowledges the genuine difficulty faced by patients on lawfully prescribed medicines who also need to drive, particularly in regional communities. Its concern is not directed at patients, but at whether the framework can be reconciled with road safety.
THC impairment cannot be accurately measured
Unlike alcohol, where concentration supports valid inferences about impairment, there is poor correspondence between THC levels in blood or saliva and driving-related impairment. THC-induced impairment can persist long after measured levels have declined, and the correlation between concentration and impairment is weakest in regular users; the group most likely to be using medicinal cannabis. A regulatory threshold therefore cannot, on present science, reliably distinguish an impaired driver from an unimpaired one. (Metrik et al., Current Addiction Reports 2026).
The “three-strike” approach is inconsistent with other impairment laws
Under the proposal, a prescribed driver who returns a laboratory THC result at or above the threshold receives a warning on a first and second detection, with penalties applying only at a third detection within two years. This differs markedly from the way the law treats other causes of impairment and drivers without a valid cannabis prescription who might have an identical THC level.
A driver who exceeds the prescribed alcohol limit faces a penalty on the first occasion as do those with impairment from other prescription medicines, or from fatigue. Establishing a separate, more permissive enforcement pathway for one substance, particularly one for which impairment cannot be measured, is difficult to justify on road-safety grounds and risks undermining the consistency of the broader drug- and drink-driving framework.
The Committee asks that the Government defer the proposed changes while it invests in research into validated measures of cannabis impairment. It also recommends Government support for affected patients directly through prescriber counselling and transport-access measures, so that patients’ needs are met without compromising road safety.
