Alcohol and/or drugs can have a significant effect on a person's ability to drive.

Effects of alcohol

However, the effect of alcohol varies greatly from person to person. It is affected by a variety of factors, such as:

See the Drug and Alcohol Services South Australia fact sheet on Blood alcohol concentration.

Drink driving offences

All references in this part are to the Road Traffic Act 1961 (SA) unless otherwise stated. The Act creates four major offences:

The elements of each of these offences is discussed in the following sections.

Specific offences apply where a person is caught drink or drug driving while a child aged under 16 years is present in the vehicle at the time of the offence.

See also our fact sheet Drink Driving and the Law Fact Sheet.

Meaning of vehicle and motor vehicle

The drug and alcohol offences under the Road Traffic Act 1961 (SA) apply either when a person drives, or attempts to move, a 'vehicle' [s 47] or a 'motor vehicle' [ss 47B or 47BA].

The definition of vehicle includes motor vehicles, trailers, trams, bicycles, animal-drawn vehicles and animals being ridden or drawing vehicles, and motorised wheelchairs that can travel at more than 10km/h [s 5].

The definition of motor vehicle is 'a vehicle built to be propelled by a motor that forms part of the vehicle' [s 5]. This is an incredibly broad definition and includes e-scooters and other electric personal transporters.