Almost all jurisdictions of the world prohibit driving on alcohol. What exactly constitutes the offence — as well as the procedures followed by police and courts and the penalties — vary greatly from one place to another; those discussed below apply mainly to Australia, specifically the state of Western Australia.
As in all the Australian states, drunken driving laws are based in large part on the Road Traffic Act of 1974, being outlined in Part 5, Division 2; specific passages therein will be indicated throughout this article.
In each state, the BAC level required for drunk driving charges depends on the type of vehicle being driven. In Western Australia, the limit is 0.02 percent for those who are taking driver’s training; have been convicted of a drunk driving offence within the past three years; or have refused to take the required blood, breath or urine test (described in the next section). Until 2008, this limit also applied to those who hold probationary licences, but that year it was set at zero. It is 0.05 percent for all other drivers. Having a BAC between 0.08 and 0.15 constitutes a separate crime, as does being over 0.15, for which the penalties are most severe.
While law enforcement officers in the United States and Great Britain are generally required to have reason to suspect alcohol or drug use, Australian law allows police to stop any driver and require him or her to take a random breath test, with or without cause. At certain special times when the level of traffic is especially high — for instance, during a sports event or on Friday or Saturday — roadblocks may be set up for every driver to undergo such a test. Those who refuse to comply face criminal charges for which the penalties include prison.
In addition to alcohol, the police are authorised to perform saliva tests for cannabis, methamphetamine and MDMA (another drug of the meth class); the limit for all three drugs is zero. The person on whom such substances are found — or whose BAC is shown to be above 0.08 percent — may be arrested without a warrant (64.1).
The suspect, upon being arrested, has the right (63.4) to be examined by a doctor whom he nominates, if one is available and to communicate with a lawyer and with another person, whom he again nominates. These rights apply only if the person was under arrest at the time of his or her arrest, and the right to medical examination does not apply if the person’s blood has been taken pursuant to section 66, 66b or 66e before he has been formally charged (4-4b).
In court, the prosecution is required to prove at least one of the following :
1-The defendant drove, or at least attempted to drive, a motor vehicle or
2- There was at least one intoxicating drug in his system at that time or
3- The behaviour was consistent with that of someone who had taken such drugs, or would not be consistent with that of a person who was in proper condition to operate a motor vehicle
The penalties for drunk driving in Western Australia depend on (1) the BAC content of the offender at the time of arrest, and (2) whether this is a first, second or subsequent offence (table, 64.2b). For instance, if BAC was between 0.08 and 0.09 and it is a first offence, the penalty is from ten to thirty PUs (penalty units; see next paragraph for an explanation of this) and a ban from driving of up to six months. Naturally these figures are increased for the second offence and afterwards. Other possible charges are outlined in Sections 64, 64aa, 64ab and 64ac.
Penalty units are an important part of Australian criminal law. They constitute a way of calculating the fines incurred for various violations of statute law. Under this system — which various among the states, territories and federal government — the fine is multiplied by the number of penalty units and the result is imposed on the offender. In the example above, if the fine is $45 and the PU is 17, then the total fine imposed would be $765.
Drivers who repeatedly violate the law may have their licences revoked for life. They may also be imprisoned.
A person who is brought to court for drunk driving proceedings need not be charged with the offence. If the defendant was under the influence of drugs, he or she may be able to use the defence that they had been prescribed or administered by a physician, a dentist or a nurse practitioner for therapeutic purposes and that he did not know they could impair his ability to operate a motor vehicle, nor could anyone have reasonably expected him to know that (63.7).
Most of what has been said above applies to the United States and other countries as well; what differs are the details, such as the figures regarding BAC, the amount of fines and length of sentences. Also, as stated above, police can stop drivers and require a breath test in Australia but not in the United States.