Technical Paper 3:
Preventing Alcohol-related harm in Australia: a window of opportunity
4.4 - Drink-driving countermeasures
Drink-driving laws and the associated programs of enforcement and social marketing are considered to be one of the great public health success stories of the late 20th century. In Australia, state and territory laws allow a Blood Alcohol Content (BAC) of up to 0.05% while driving for full licence holders, 0.00% for learner drivers and 0.00 per to 0.02% for provisional drivers, depending on the state or territory. Those who operate commercial aircraft, public or heavy vehicles, commercial vessels, machinery and mobile plant or farm equipment must observe the BAC restrictions required by their employer, as well as those required by law. For most adults, drinking no more than two standard drinks on an occasion will maintain their BAC below 0.05%. The evidence for the deterrent effect of such laws is strong, although the effects can erode over time and hence some countries have continued to lower BAC limits.[13] From the 1970s, Australian states world leaders in driving down rates of drink-driving through random breath tests and other means.
There is some evidence, albeit tentative, that having lower BAC limits for young drivers reduces the risk of road fatalities, especially if the BAC limit is 0.00%.[7] More broadly, there is good evidence that lower BAC limits, delayed access to full licence and curfews for young drivers can be effective in reducing drink driving among young people; graduated licensing schemes can potentially incorporate all of these measures within a single system.[13]
Random breath testing (RBT) has been shown to be effective in several countries, including Australia, in reducing road crashes, injuries and fatalities.[7] The defining feature of RBT is that any motorist at any time may be required to take a breast test, and there is nothing they can do to influence their chances of being tested.[13] Research suggests that there is a strong tendency for motorists to comply with drink-driving laws in jurisdictions that use RBT programs because of the uncertainty about the real risk of detection.[13] Herein lies part of the impressive cost effectiveness of random breath testing. RBT is considered a superior method of enforcing drink-driving laws than sobriety checkpoints, which only check drivers who are judged to have been drinking.[13] In Australia, creating the public perception that there is a high chance of being caught drink driving through RBT has been achieved by a combination of high-visibility policing (road blocks, ‘booze buses’) and frequent social marketing campaigns that emphasise the likelihood of drink drivers being detected.[7]
Among the range of punishments for drink driving, the penalty that appears to have had the most consistent impact is licence suspension.[13] Increasing the severity of fines and imposing penalties such as imprisonment for drink driving have not been shown to result in reduced rates of drink driving or car accidents.[13] However, it is estimated that up to 70% of people who lose their licence continue to drive while unlicensed, as the risk of apprehension is relatively low.[43] The major concerns with disqualified drivers continuing to drive are that it undermines the effectiveness of licence suspension and is also linked to a range of other high-risk behaviour such as repeated drink driving and speeding.[43] Court diversion of drink drivers to educative and mandatory treatment interventions and the incapacitation of vehicles using ignition interlock devices are regarded as effective means of increasing compliance with licence suspension and reducing recidivism.[7, 13]
While there is no evidence that on-premise designated driver programs produce negative effects, the impact of such programs is very modest and even with concerted promotions they only produce a small positive effect.[13] An Australian review of these schemes was somewhat more supportive, pointing to research findings that the programs do have some positive influence on the behaviour of young people in selecting a sober driver, and that given the cost of such programs is usually borne by licensed premises, there is no opportunity cost in recommending such schemes.[7]