How do amphetamine-type stimulants affect driving?

Amphetamine-type stimulants (ATS) include methamphetamine, ecstasy, cocaine and some pharmaceuticals (e.g. dexamphetamine and Ritalin).

Using amphetamines puts you at a similar level of risk as that of a driver with a BAC above 0.05 (Arrive Alive 2008).

Amphetamine-type stimulants are a group of drugs that include both prescription medicines, and some illegal substances (including "speed" or "ice"). The following information refers to the use of illegally produced methamphetamines.

If you are using an amphetamine-type stimulant prescribed by a doctor, see "Medications and safe driving". You should also discuss the effects of the drug with your doctor.

Amphetamine-type stimulants are stimulant drugs. They speed up the activity of the central nervous system, including the brain.

What can influence the effects?

The effects of amphetamine-type stimulants can be different for each person. They may be influenced by:

how much is used. Larger amounts can produce different effects.
how strong or pure it is. What other substances does it contain? There is no quality control on illegally manufactured drugs, so producers can include any substances they have.
the body and mind of the person using it. A person's mental or emotional state and physical health can alter the drug's affects.

Driving difficulties

It is difficult to predict exactly, in what way and for how long, amphetamine-stimulants will affect the ability to drive safely.

As a general guide, amphetamine-type stimulants can cause:

lapses of attention
disorientation
lack of coordination
difficulty reacting appropriately to safely control a vehicle
aggressive, dangerous driving
increased risk taking
overconfidence in driving skills
drowsiness or rebound fatigue (as the effects wear off).

"Come down" effects (exhaustion, difficulty concentrating, irritability and depression) after using amphetamine-type stimulants may also impair driving ability.

A person who has been using amphetamine-type stimulants may think that if they are especially careful they will be able to drive safely. However, the drug may have affected their view and experience of reality. Their actions and responses may be quite different to what is actually needed, but they may be unaware of how much their driving skills have been affected.

As a rough guide, the devices in Victoria's random roadside saliva testing can detect methamphetamines for approximately a day or more after the last use.

Find out more about roadside drug testing.

Safer driving tips

The effects of amphetamine-type stimulants may last up to 12 hours, and the "come down" effects, like exhaustion, mood swings and depression may continue for longer. If you intend using amphetamine-type stimulants, the safest option is not to drive.

If you have used amphetamine-type stimulants, make sure that you have had several hours of sleep after your last use. At first, amphetamine-type stimulants may make you feel alert, but as they wear off, and you "come down", you may start to feel exhausted and fall asleep.

Find more information for drivers.