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The avoidable costs of alcohol abuse in Australia and the potential benefits of effective policies to reduce the social costs of alcohol

5.3 Measures to reduce drink driving

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The current Australian drink-driving policy environment consists of a blood alcohol concentration (BAC) limit of 0.05, backed by an enforcement regime of random breath testing (RBT). The research literature indicates that there are two possible, evidence-based, approaches to the reduction of the social costs of alcohol-attributable road accidents:

• a more intensive enforcement regime of the BAC limit; and
• lowering the legal BAC level.

5.3.1 Greater enforcement of random breath testing

There is substantial evidence that random breath testing loses much of its effect if levels of enforcement are too low or if the enforcement effort is insufficiently well targeted. For example, a Federal Office of Road Safety paper by Henstridge et al. (1997) found that the New South Wales RBT, which was introduced in that state in 1982, ‘almost ceased to have any impact on some series of accidents in the late 1980s due to the decay in the introduction effect and was “saved” only by increased levels of enforcement that had a substantial “residual deterrent” effect’. Residual deterrence represents the lagged effects of enforcement. Henstridge et al. (1997) point out that the population of NSW makes possible more detailed analysis than for the other states.

The model for all serious accidents suggests that an increase of 1,000 in the daily testing rate corresponds roughly to a decline of six per cent in accidents (within the range of observed data, which is 2,000 to 6,000 with a spike at 8,400) … However, from the models the relationship between changes in daily testing rates and accident reductions is not linear, so that there is an element of “diminishing returns” as daily enforcement levels increase. (p. 50).

Because a log-linear model was the basis of the analysis, the relationship … is not quite linear. For example, an increase in daily testing levels of 1,000 corresponds to a reduction of 5.9 per cent in serious accidents, but an increase of 3,000 corresponds not to a 17.7 per cent but to a 16.6 per cent reduction. The greater the increase in testing levels, the more the reduction in accidents falls below what would be predicted from a straight line relationship. (p. 40).

Henstridge et al. (1997, p. 115) include as one of their recommendations the following:

All States should increase highly visible stationary RBT to a level equivalent to one test per licence holder per year. This could be accomplished in a cost effective manner by using general duties police, and possibly also booze buses, and by utilising the management techniques embodied in the random roadwatch program.

On the information provided by Henstridge et al., the average number of tests per licence holder per year in the four states investigated (New South Wales, Tasmania, Western Australia and Queensland) in 1995 was 0.53. There appears to be no current published information on RBT in Australia, so the assumption is made for the purposes of this study that the 2004/05 rate was the same as that in 1995. Thus, adoption of the Henstridge et al. recommendation of increasing the rate to one test per licence holder per year would involve an increase of 90 per cent in the number of tests. This translates, on the basis of the relationship set out above, to a reduction of approximately 30 per cent in serious accidents. The present study adopts this recommendation as being an externally validated and feasible target. Estimates are also made for a range of assumed accident reduction, with the minimum being 25 per cent and the maximum 35 per cent.

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5.3.2 Reducing the blood alcohol concentration level

There is little international experience of BAC levels below the current Australian level of 0.05. However, evidence from the Swedish experience indicates that a reduction of the BAC level in that country in 1990 from 0.05 to 0.02 led to a reduction in fatal alcohol-related accidents of between eight per cent and ten per cent (Anderson & Baumberg, 2006). For the purposes of the present study, it is assumed that a reduction in the Australian BAC limit to 0.02 would lead to a reduction of nine per cent in alcohol-attributable road accidents, with the lower and upper boundaries used in sensitivity testing being eight per cent and ten per cent.

5.3.3 Conclusions from the research evidence

Anderson and Baumberg (2006, p. 250) conclude that:

The drink-driving policies that are highly effective include lowered blood alcohol concentration (BAC) levels, unrestricted (random) breath testing, administrative license suspension, and lower BAC levels and graduated licenses for young drivers … To be effective, drink driving laws must be publicized. If the public is unaware of a change in the law or an increase in its enforcement, it is unlikely that it will affect their drinking and driving. When incorporated as part of community programmes, drink driving measures appear to have increased effectiveness.

The table below presents their summary of the strength of the research evidence on drink driving countermeasures.

Table 19. Effectiveness ratings for drink driving countermeasures

	Effectiveness	Breadth of research support	Cost efficiency
Lowered BAC levels	+++	+++	+++
Random breath testing	+++	++	+
Licence suspension	+++	++	++
Lower BAC for youth	+++	++	+++
Graduated licensing	++	++	+++
Community programs	++	++	+

Source: Anderson and Baumberg (2006, Table 7.3).
For the de?nitions of the ratings see Table 6 above.

5.3.4 Potential reductions in social costs from anti-drink-driving policies

It is assumed that the above percentage reductions in attributable road accidents can be translated, over a period of time, into the same percentage reductions in the tangible and intangible social costs of these road accidents. Since enforcement levels are an important determinant of the effectiveness of BAC legislation, the benefits of the two approaches, in terms of cost reductions, are treated as being additive.

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The next four tables below present estimates of the benefits which would result from the implementation of the two anti-drink-driving initiatives discussed above.

Table 20. Reduction in social costs resulting from increased RBT enforcement (2004/05 prices)

	Best estimate $m	Minimum $m	Maximum $m
Tangible costs	660	550	770
Intangible costs	280	230	320
Total costs	940	780	1,090

Table 21. Reduction in social costs resulting from lowering BAC level to 0.02 (2004/05 prices)

	Best estimate $m	Minimum $m	Maximum $m
Tangible costs	200	180	220
Intangible costs	80	70	90
Total costs	280	250	310

Table 22. Reduction in total social costs resulting from anti-drink-driving initiatives (204/05 prices)

	Best estimate $m	Minimum $m	Maximum $m
Increased RBT enforcement	940	780	1,090
Lowering BAC to 0.02	280	250	310
Total	1,220	1,030	1,400

Table 23. Reduction in total social costs resulting from anti-drink-driving initiatives (2004/05 prices), tangible and intangible

	Best estimate $m	Minimum $m	Maximum $m
Tangible costs	860	730	990
Intangible costs	360	300	410
Total costs	1,220	1,030	1,400

Increased enforcement would yield benefits estimated to be in the range $780m to $1,090m, with the best estimate being $940m. Lowering the BAC level to 0.02 would yield estimated benefits in the range $250m to $310m (at 2004/05 prices), with the best estimate being $280m.

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