Drugs and driving update
A person who drives a vehicle under the influence of alcohol and other drugs (including some prescription and over the counter medications) poses a potential hazard to themselves, any passengers and other road users.
Alcohol and other drugs impair a person's driving in various different ways. Even in low doses, alcohol can significantly reduce driving performance by reducing braking time, speed control and diverting attention. It can also contribute to motorists weaving between lanes or driving abruptly or aggressively1. For example, research shows drivers with a 0.5 per cent blood alcohol concentration (BAC) react much slower to potential road hazards than when they are sober2.
A driver affected by cannabis may drive too slowly and find it difficult to drive within designated lanes or stay awake1.
Amphetamines and ecstasy can lead to speeding or erratic driving as well as reduced vision and increased risk taking behind the wheel1.
More information on how different substances affect driving can be found here:
Drug driving is a serious road safety issue. For example, in Victoria more than one-third (37%) of all drivers and motorcyclists killed on Victoria roads during the past five years had drugs in their system, with cannabis and stimulants the most common substances detected. The Victorian data revealed approximately 21% of drivers and motorcyclists killed in 2012 tested positive to cannabis, ecstasy, speed, or crystal methamphetamine ('ice')3.
Australia's approach to reducing drug driving rates focuses on detection through roadside drug testing, and education initiatives.
Police use roadside drug tests to detect the presence of illegal drugs such as cannabis, methamphetamine and ecstasy in a motorist's body. It should also be noted that if you are injured in a motor vehicle accident and transported to a hospital you will be asked to provide a sample of blood which will be analysed for drugs and alcohol.
Increased roadside testing in Australia in the past few years has led to police detecting more drug-affected drivers, however it is too soon to tell if it is likely to deter people from driving under the influence4.
In Victoria, there are a number of prevention strategies to help prevent drug driving.
Victoria's Transport Accident Commission's (TAC) drug-driving campaign began in 2004 and was designed to coincide with the introduction of roadside drug testing and focused on the risk of detection. TAC has also developed a wide range of primary and secondary school resources aimed at teaching the next generation of drivers about road safety, peer behaviour, decision-making and how choices can affect others.
Driver education is also considered a prevention strategy when used as part of the license restoration system. When someone loses their license they must undertake an education course and when combined with fines and disqualification periods, this has been shown to be an effective deterrent1.
Another prevention strategy is being implemented by pharmacists (when dispensing prescriptions) who are required to advise consumers about the possible effects of medicines on driving performance. This is achieved through warning stickers on medications and combined with verbal information1.
All of these approaches work together to reduce the number of individuals who drive under the influence of drugs.
Alcohol and other drugs can continue to affect a motorist long after the effects of the substances wear off, which means people still pose a risk even if they feel safe to drive. People may also feel tired or hung over when the drug effects wear off which can also impair their driving ability.
For that reason it is best to avoid driving altogether if alcohol or other drugs have been consumed.
All drivers, whether young or old, should avoid driving if they have recently consumed alcohol or other drugs.
Strategies to avoid drug driving and stay safe:
It is important to remember that alcohol and other drugs can continue to affect you the next day4.
A motorist who has taken prescription medication, whether legally or illegally, should be aware of the potential risks while driving. Some warning signs may include feeling drowsy, aggressive, dizzy, nauseous, light-headed or shaky. They also may experience problems with their vision.
If taking prescribed or over-the-counter medication, always:
1. Stough, C. & King, R. (2010). Drugs and driving. Prevention Research Quarterly, 12, 1–32.
2. Deery, H.A. & Love, A. W. (1996). The effect of a moderate dose of alcohol on the traffic hazard perception profile of young drink-drivers. Addiction, 91:6, 815–27.
3. Transport Accident Commission. (n.d.) Drugs and Driving.
4. Monash University Accident Research Centre. (2007). Going Solo - A resource for parents of P-plate drivers.
Last updated: 7 June 2016