Kevin Clinton, head of road safety at the Royal Society for the Prevention of Accidents (RoSPA), was speaking after figures from Tayside Police revealed over 400 individuals in the area have been caught driving while under the influence of various substances since 2008.
The majority of those charged were stopped by police while over the legal alcohol limit, including one driver who was aged just 15.
However, Mr Clinton insisted that drug driving was becoming an increasing concern to road safety campaigners and called for “more effective” methods of testing for illegal substances in order to crack down on the problem.
At present specially trained officers must carry out preliminary tests on drivers they believe to be unfit to drive due to having taken drugs.
A series of examinations, including a balance test and a counting test, are used to determine whether the officer believes the driver is impaired through having taken certain substances.
If drivers are believed to be guilty they will be requested to report to a police station for a medical examination and a blood sample may then be sent for testing.
However, Mr Clinton believes the length of the process may skew the results and roadside testing could act as a “greater deterrent” to potential drug drivers.