DESCRIPCIÓN DEL PROCESO

In 2013, four European Member States had offender programmes in place: Belgium, Finland, The Netherlands and Sweden. The Swedish programme is the oldest; it started already in 1999. The Belgian programme was introduced in December 2010, but so far only one driver has been included in the program. In the Netherlands the programme started in December 2011 and around 4,000 drivers have been included in the programme in the first two years. In Finland, an offender programme was introduced in 2008 and in the first four years approximately 1,700 drivers entered the programme.

5.1.1 Method for assessing safety benefits of offender programmes

The effectiveness of alcohol interlock offender programmes depends on three elements:

1. the total number of alcohol related fatalities related to heavy offenders;

2. the road safety effect of alcohol interlocks;

3. the penetration level of alcohol interlock offender programmes.

Data regarding these three elements should be gathered for all countries. A Dutch cost-benefit analysis (SWOV, 2009) also used these three factors to estimate the effect of an alcohol interlock programme for offenders in the Netherlands.¹⁷ At the time of the analysis it was not yet clear whether the programme would have a standard duration of two years with one prolongation of 6 months for recidivists or whether an unlimited number of prolongations would be included for recidivists.

In this study for the Netherlands, it was estimated that the total number of offenders in the Netherlands was 100,000, 1% of all driving licence holders. These offenders drive 10% of their driven kilometres with high BACs.

For the programme with only one prolongation it was estimated that 4.5% of the offenders in the Netherlands would be permanently included, and for the programme with the unlimited number of extensions it was 6%. Furthermore, it was estimated that the reduction in driving under the influence for these drivers would be 75%. The overall effect on road safety was estimated, respectively on a 3.4% and a 4.5% reduction of the total number of alcohol related road fatalities.

For calculating the European estimate it would in theory be most sound to use the same three elements of the calculation for all countries. However, in practice these data are sparse, dispersed

17 The interlock programme was not aimed at all offenders with high BACs, since they have to undergo a medical-psychological test to see whether they are alcohol dependent. If this is not the case, they will be eligible for the program.

over several sources and the available data difficult to compare. Therefore, we base our estimates on information available at European level. The estimates are therefore not usable on the level of individual Member States.

Alcohol related fatalities due to heavy offenders

It is estimated in chapter 2 that the share of alcohol related fatalities in the European Union is around 25%. Results of the DRUID project (Isalberti et al., 2011) show that approximately 75% of all seriously and fatally injured drivers that tested positive for alcohol, are drivers with high BACs (1.3 g/L or higher). The European alcohol related road toll of heavy offenders is thus estimated to be 19% (=75% x 25%). As argued in chapter 2, for these high BAC offenders it may be assumed that all crashes could have been avoided when they had not used alcohol.

Road safety effect of alcohol interlocks for heavy offenders

The Dutch cost-benefit analysis (SWOV, 2009) assumed, based on international literature, that alcohol interlock programmes are 75% more effective in reducing recidivism than suspension of the driving licence. However, the CBA does not give the effect of driving licence suspension, which makes it difficult to quantify the effect of alcohol interlock programmes.

In their handbook of road safety measures Elvik et al. (2009) mention three studies that have evaluated the effect of licence suspension after alcohol use on road crashes. One of these studies (Hagen et al., 1978) found that a six year driving licence suspension resulted in a reduction of 25%

in the number of alcohol related crashes. The other two studies (Preusser et al., 1988; Siskind, 1996) report a reduction of all road crashes varying between 16% and 65%, depending on the target group and the severity of the crash.

For this analysis we assume that the effect on alcohol related crashes would be higher than 25% in case of a 2 year ban, since suspended drivers will be more likely to drive without a licence during a longer suspension period. We therefore use three scenario’s for the effect of suspension of the driving licence, namely 25%, 40% and 50%. These shares are rough estimates, but within the margins that were found in the studies by Preusser and Siskind. Taking a 75% higher effectiveness for alcohol interlocks the overall net effectiveness of alcohol interlocks, as compared to suspension of the driving licence, can be respectively assessed at a reduction of 18.75% to 37.5% reduction in alcohol related crashes in the three scenario’s.

Elder et al. (2011) reported in their systematic review that the effects of the installation of alcohol interlock devices were only visible during the period when the devices were installed. After removal of the alcohol interlock devices, differences in alcohol use with alcohol offenders who had not an interlock devices installed in their vehicle were no longer visible. Therefore, we include in this analysis a road safety effect for the instalment period only, not for the period after removal.

Penetration level of the measure

The penetration level of the measure depends on the share of heavy offenders that is arrested by the police and the share of arrested heavy offenders that participate in the alcohol interlock programme.

Results from the European Sartre Study in 2010 (SARTRE, 2012) show that 15% of all interviewed drivers in 18 European countries reported to have driven with alcohol over the legal limit in the past month. The US National Survey on Drug Use and Health shows that in 2010 an estimated 15.1 per cent of 18 to 20 year olds reported driving under the influence of alcohol in the past year (NSDUH, 2011). Among persons aged 21 to 25 this was even 23.4 per cent. Beyond age 25, these rates

show a general decline with increasing age, with persons aged 55 to 59 at 10.1%, persons aged 60-64 at 6.4%. Persons aged 65+ had the lowest share at 2.7%.

No overall figure is given by this survey, but based on the distribution over the different age classes of the self-reported share of drink-driving in the past year, it will probably have been around 15%.

As self-reported alcohol use may give an underestimation of the real share of drink-driving

offenders, we assume for this study that 15-20% of the drivers in the European Union drive at least once a year with a BAC above the legal limit. There are no data, however, on the share of drivers that are driving with high BAC-levels.

An estimate of alcohol use on European roads which is based on the results from the European DRUID project shows that 1.49% of the drivers were driving with a BAC over 0.5 g/L which is the legal limit in approximately two thirds of all European countries. Seven countries of the 27 countries (with 23% of all road fatalities in Europe) in this study have BAC limit of 0.0 g/L or 0.2 g/L. The average share of drivers in the EU that is over the 0.1 g/L is 3.45%. Furthermore, the results of the DRUID study show that 0.39% of the drivers were driving with a high BAC of 1.2 g/L or higher.

The actual share of high BAC offenders is probably higher, since offenders may have been warned for the road side checks by e.g. social media. In the Dutch cost-benefit analysis (SWOV, 2009), the actual share of high BAC offenders was estimated to be around 1% of all drivers. Given the available information this seems the best estimate.

Furthermore, an estimated annual arrest rate of 10% was used in the Dutch cost benefit analysis.

Based on the share of alcohol use in Dutch traffic, in relation to the European mean, it may be assumed that approximately 7.5 to 10% of the high BAC drivers are arrested by police on a yearly basis.

Of those heavy offenders who are caught during an alcohol police check, only a part will choose to drive with an alcohol interlock. The share of participants depends on several factors, such as whether the alcohol interlock is sentenced by court or whether it is an administrative measure. We have therefore included three scenarios for participation rates: a low scenario of 10% based on the early Swedish experience and the experience of the share of offenders in California that were sentenced by court of alcohol use; a middle scenario of 50%, which can be regarded as a high participation rate of alcohol interlock programmes that presently run; and a high scenario of 70%

that represents a more optimal situation, but would be less feasible at present. These participation rates are more in less in line with participation rates reported by Elder et al. in 2011 (1%-63%;

median 13%).

5.1.2 Estimate of safety benefits of offender programmes To summarize the above:

• Around 1% of the driving population is (sometimes) driving with high BAC levels;

• Some 7.5%-10% of the high BAC offenders are expected to be caught;

• The participation rates of these offenders in alcohol interlock programmes is unsure an may vary between 10% and 70%;

• The net effect of an alcohol interlock as compared to suspension of the driving licence, in terms of a reduction in traffic fatalities ranges between 18.75 and 37.5%;

• and the alcohol related road toll related to high BAC offenders is 18.75% (=75% of 25%) of the total number of road deaths.

Table 5.1 – 5.3 present the estimated number of avoided road fatalities in various scenario’s, under the assumption that all alcohol crashes could have been avoided if no alcohol would have been used. In the cost benefit analysis in chapter 9 also a more conservative assumption will be used.

The figures represent the total number of prevented road fatalities per scenario that are assumed to be avoided due to the implementation of an alcohol interlock programme in the European Union, given 2010 data.

Table 5.1 Estimated number of prevented road fatalities per year at an estimated effect of the alcohol interlock programme for heavy offenders of 18.75% reduction of the number of alcohol related fatalities 18.75% reduction alcohol related

Table 5.2 Estimated number of prevented road fatalities per year at an estimated effect of the alcohol interlock programme for heavy offenders of 30% reduction of the number of alcohol related fatalities

30% reduction alcohol related crashes Penetration

7.5% 10%

Participation 10% 26 34

50% 128 171

70% 179 239

Table 5.3 Estimated number of prevented road fatalities per year at an estimated effect of the alcohol interlock programme for heavy offenders of 37.5% reduction of the number of alcohol related fatalities

37.5% reduction alcohol related

This means that depending on the scenario it is estimated that approximately between 16 and 299 road fatalities per year could be avoided with an alcohol interlock programme for heavy offenders instead of a driving licence suspension.

The relatively low numbers of road fatalities saved, as estimated above, are mainly due to the relatively low risk of being arrested for driving under the influence. Rauch et al. (2010) report for instance estimates from the Unites States that drivers can drive 200-2000 times under the influence of alcohol before being arrested.