Conclusions of Chapter 8

Epidemiological data

Data on effects on driving

Testing

Further studies

âØ            Between 5% and 12% of drivers may drive under the influence of cannabis; this percentage increases to over 20% for young men under 25 years of age.

Ø      This in itself does not mean that drivers under the influence of cannabis represent a traffic safety risk.

Ø      A not insignificant percentage of drivers test positive for cannabis and alcohol together.

âØ            Cannabis alone, particularly in low doses, has little effect on the skills involved in automobile driving.

âØ            Cannabis, particularly in the doses that match typical doses for regular users, has a negative impact on decision time and trajectory.

âØ            Cannabis leads to a more cautious style of driving.

âØ            The effects of cannabis when combined with alcohol are more significant than for alcohol alone.

âØ            Blood remains the best medium for detecting the presence of cannabinoids.

âØ            Urine cannot screen for recent use.

âØ            Saliva is promising, but rapid commercial tests are not yet reliable enough.

âØ            The visual recognition method used by police officers has yielded satisfactory results.

It is essential to conduct studies in order to:

âØ            Develop a rapid testing tool.

âØ            Learn more about the driving habits of cannabis users.