Cannabis and driving
Safe driving requires the driver to pay attention to many things at once and to be able to react quickly when something unexpected happens.
All drivers need:
- to be mentally alert;
- to have clear vision;
- physical coordination; and
- the ability to react appropriately.
Impairment of any of these driving abilities can increase the risk of having a crash.
The dangers of driving after using cannabis include that the driver:
- takes longer to react, especially to emergency situations;
- their ability to think clearly is reduced, making it difficult to perform the multiple tasks required in order to drive safely;
- their ability to pay attention is reduced, such as not noticing other road users; and
- may have blurred vision and reduced hearing.
What happens when cannabis is used?
When cannabis is smoked the effects are experienced very quickly and may last up to 5 hours. When cannabis is eaten, the onset of effects may be delayed by about 60–90 minutes and can last up to 24 hours.
A person who uses cannabis may think they can alter their driving to counteract any impairment to their driving ability. However, this is a dangerous approach, as the effects of cannabis may mean that the driver:
- fails to notice something they would normally have observed;
- may have an altered view and experience of reality — their actions and responses may be quite different to what is actually needed; and
- may be unaware how much their driving skills are affected after using cannabis.
For more information, please click on the Australian Drug Foundation's DrugInfo Clearinghouse web site link below.
Last Reviewed: 20 September 2006
