An explosion in drug driving charges over the past decade is likely the result of an expanded NSW detection program rather than any chances in public behaviour.
The state's crime statistics bureau on Wednesday released a report that questioned the deterrent effect of the testing scheme, which has dramatically grown during a nine-year period.
More than 13,800 drug driving offences were recorded across NSW in 2023, up a staggering 836 per cent from the 1409 logged in 2014.
However, only 39,000 tests were performed that year, a tally that had grown to 156,000 by 2023.
There was no evidence the increase was driven by a change in drug use or driving behaviour, the NSW Bureau of Crime Statistics and Research said.
"The study provided evidence that police continue to prioritise the safety of motorists … despite the NSW mobile drug testing (MDT) program being one of the largest in Australia, the volume of tests is still small relative to the number of registered drivers," executive director Jackie Fitzgerald said.
"This may limit the general deterrent effect of the program."
The drug detection rate was less than three per cent before 2014 but reached 15 per cent by 2015, when about 62,000 tests were carried out.
The proportion of tests that returned positive results then dropped as volumes increased, falling to a six per cent detection rate in 2019 on 166,000 tests.
"While the MDT expansions aimed to increase police capacity to detect and deter drug driving behaviours, we found only a weak and inconsistent relationship between total testing volumes and subsequent detection rates," the bureau's report said.
The small scale of the police's roadside drug testing program might be undermining its deterrent affect as it limited the actual and perceived risk to offenders, it added.
"A large and growing number and proportion of drug driving offenders continue to be proceeded against for a reoffence (which) implies that the program may not have a strong specific deterrent effect," the report said.
