OPINION: Around one quarter of deaths on Australia’s roads involve drink-driving. Over a decade, this amounts to over 3,500 deaths, as well as many thousands of serious injuries.

While the most common death in a drink-driving crash is the drink-driver, many victims are innocent pedestrians, occupants of other vehicles, and other road users who happened to be in the path of the drink-driver.

Far from improving, data on drink-driving trends show the problem is getting worse.

Across Australia, the general driving and riding population has a legally allowed blood alcohol concentration (BAC) limit of .05, which has been in force for over 30 years. But technology, attitudes and knowledge have improved. So isn’t it time to reconsider this BAC limit?

Around 30 years ago and for many years, Australia led the world in drink-driving regulation and enforcement. Victoria led the introduction of random breath testing (RBT), and New South Wales was the first to run RBT on a massive scale and prove its power. The rest of Australia and many other countries followed those leads.

Now, despite widespread use of RBT, Australia has slipped behind many other countries.

The European Transport Safety Council’s 2012 Drink-Driving: Towards Zero Tolerance report recommends all European Union member countries move to zero BAC limits (possibly with a small tolerance). Many European countries have already made the move, with Sweden, Poland, Slovenia and Estonia enforcing .02 limits, and Hungary, Czech Republic, Romania and Slovakia adopting .00 BAC limits.

We may still see ourselves as different from these countries in that we simply drink more. Not so.

The World Health Organisation’s 2011 Global Status Report on Alcohol and Health placed countries into categories of pure alcohol consumption per capita, and found that Australians ranked in the 10-to-12.49 litres per person (per year) category. Of all the European countries mentioned above, four (Sweden, Belgium, Greece and Austria) ranked in the same range as Australia, while all the rest ranked in the highest consumption range (12.5 litres or more per person, per year).

It’s important to note that the aim of drink-driving reform is not to reduce drinking – though this may be of value for other health reasons. The aim is to disconnect drinking from driving.

So what evidence is there to support a case for reducing the BAC limit to .02 or even zero?

We know alcohol affects behaviour and cognitive functioning, even at low concentrations. This increases the time drivers take to make decisions and reduces their capacity for precise motor movements. Alcohol also reduces inhibition and increases confidence and risk-taking.

Lower limits, especially a zero tolerance approach, reduce the risk of inaccurate estimates of BAC. The same level of alcohol consumption can affect individuals differently and result in wide variations in BAC. For this reason, counting drinks isn’t an accurate method for avoiding drink-driving.

Previous Australian experience in lowering BAC limits also offers support. When the ACT reduced the BAC limit from 0.08 to 0.05, random breath tests showed a 34% reduction in the number of drivers with a BAC between 0.15 and 0.20, and a 58% reduction in the number with a BAC above 0.20. Well beyond just affecting the low range drink-drivers, these results support the logic that lowering BAC limits reduces misjudgement and risk-taking decisions made under the influence of alcohol.

Internationally, Ireland’s large reduction in drink-driving deaths – from 37% in 2003, to 14% in 2007 – was largely achieved by lowering the BAC limit. And studies of the lowered BAC limit in Sweden identified a 10% reduction in fatal crashes related to drink-driving after the change.

The Australian National Road Safety Strategy 2011-2020, which was endorsed by the transport or roads ministers of the Commonwealth and each state and territory, references much of the evidence above in support of lowering BAC limits. It recommends that, in consultation with stakeholders and the community, we examine “the scope to reduce the legal blood alcohol concentration (BAC) limit for all drivers.”

There’s no doubt that a zero or 0.02 BAC limit would strongly reinforce the message that drinking and driving should be separate activities, and drinkers should plan alternatives to driving before they start drinking.

Assuming an effect of a similar size to Sweden, lowering the BAC to .02 could save the lives of 350 people over the coming decade, as well as saving many more from serious injuries. Is allowing the BAC limit to remain at .05 really worth these deaths and injuries?

Soames Job is the Executive Director, National Road Safety Council and Adjunct Professor, UNSW's Transport and Road Safety Research group .

This opinion piece first appeared in The Conversation.