Ministry of Justice, New Zealand

5.1 Percentage of drivers under 20 exceeding their legal breath alcohol limit
5.2 Prosecutions for driving with excess breath or blood alcohol
5.3 Drivers involved in crashes who had alcohol recorded as a factor in the crash
5.4 Summary

5.1 Percentage of drivers under 20 exceeding their legal breath alcohol limit

From 1997 to 2004, the Police have collected data from special compulsory breath testing (CBT) check-points to determine the proportion of drivers exceeding their legal breath alcohol limits. These check-point operations were conducted at randomly chosen sites at high-risk times for alcohol impaired driving (i.e. on Friday and Saturday nights between the hours of 10 p.m. and 2 a.m.).

Table 5.1 Percentage of drivers aged under 20 exceeding their legal breath alcohol limit from random roadside breath-testing data, 1997-2004

Source: Land Transport Safety Authority and Ministry of Transport.

Table 5.1 shows that between 1997 and 2004, 1% to 3% of those under 20 years old who were stopped at the roadside had excess alcohol readings. The percentages showed no clear trend of either increasing or decreasing during this period. Because of the relatively small numbers of those under 20 years old in the sample each year, there can be quite large fluctuations from year to year.

5.2 Prosecutions for driving with excess breath or blood alcohol

Prosecutions are used as a measure of traffic offending for those under 20 years old.[10] However, under the provisions of the Children, Young Persons and Their Families Act 1989 some young offenders (those between 14 and 16 years old) apprehended for imprisonable traffic offences will have a Family Group Conference and will not be prosecuted in formal court proceedings, so will not be included in these figures.[11] Information is not available on the number of Family Group Conferences that do not result in formal court proceedings.

Table 5.2 Prosecutions for driving with excess breath or blood alcohol, 1995-2004

Notes:
1 Offences included in this table relate to driving with excess alcohol (including offences where death or injury was involved). Offences related to driving under the influence of drugs are excluded, as are offences related to refusing to supply a blood specimen.
2 Although a person under the age of 15 cannot hold a driver licence, each year a number of 14 year old drivers were prosecuted for driving with excess alcohol.
3 Source: Ministry of Justice.

Figure 5.1 Prosecutions for offences committed by those under 20 years old for driving with excess breath or blood alcohol, 1995-2004

The number of those between 14 and 17 years old prosecuted for driving with excess breath or blood alcohol showed an increasing trend from 824 in 1997 to 911 in 1999. The upward trend continued in the five years following the law change, with 1184 prosecutions in 2004. (See Table 5.2 and Figure 5.1).

Figure 5.2 Total prosecutions for driving with excess breath or blood alcohol, 1995-2004

Between 1995 and 1999, the number of people 18 or 19 years old prosecuted for driving with excess breath or blood alcohol fluctuated between 1990 and 2274. In each of the years after the law change the number of such prosecutions increased and, at 2978 in 2004, was the highest recorded in the decade. (See Figure 5.1).

The total number of prosecutions for driving with excess breath or blood alcohol showed a decreasing trend from 21492 in 1996 to 19474 in 2000. For the next four years the number fluctuated around an average of 19850. (See Figure 5.2).

Because the number of drivers between 14 and 17 years old prosecuted for driving with excess breath or blood alcohol showed an increasing trend while the total number of such prosecutions showed a decreasing (stable from 2001) trend, the proportion of all drivers prosecuted for this offence who were under 18 showed an increasing trend across the decade from 4% in 1995 to 6% in 2004. The proportion of all drivers prosecuted for driving with excess breath or blood alcohol who were 18 or 19 years old was slightly higher in the five years following the law change than before the law change. The 2004 figure (14%) was the highest recorded in the decade.

Although there were increases in young people prosecuted for traffic offences involving alcohol after the purchase age was lowered, there were changes other than lowering the purchase age which may have influenced prosecutions of these young people. For example, changes in licensing procedures made drivers under 20 years old easier to identify.[12] Drivers under the age of 20 have lower allowable alcohol limits, and the driver must be identified as under 20 so that the testing equipment can be set to the correct level and the results interpreted correctly. It is not possible to quantify how much of the increase can be attributed to lowering the purchase age, however, it is likely that some of the increase can be attributed to young people having increased access to alcohol after the purchase age was lowered.

5.3 Drivers involved in crashes who had alcohol recorded as a factor in the crash

Table 5.3 shows the number and percentage of 15-19 year old drivers involved in reported injury and fatal crashes who had alcohol recorded as a factor. These data relate to the 12 month period from 1 December to 30 November the following year.

Both the number and the percentage of 15-19 year old drivers involved in crashes who had alcohol recorded as a factor that contributed to the crash decreased between 1994 and 1999. Following the law change, the number and percentage continued to decrease in 2000. The numbers increased slightly each year between 2001 and 2003, although the 2003 figures were still much lower than the figures in 1994 and 1995. Between 2001 and 2003 the percentages fluctuated at a lower level than the level between 1994 and 1995.

Table 5.3 Number and percentage of 15-19 year old drivers involved in crashes who had alcohol recorded as a factor, 1994-2003

Source: Land Transport Safety Authority, and Ministry of Transport.

Activities that have contributed to the decreases earlier in the decade include the introduction of compulsory breath testing (CBT) in 1993, and increased enforcement and advertising effort associated with the Supplementary Road Safety Package funding from late 1995.

In 1999 a number of further changes were introduced which may have contributed to the decrease in 2000. These included photo driver licences, the mandatory production of driver licences, the mandatory licence suspension regime that targets grossly intoxicated drivers, the introduction of more severe penalties for repeat drink-drive offences, and vehicle impoundment. (While vehicle impoundment directly targets illegal drivers, it may also impact indirectly on drink-drivers since many of them are also disqualified or unlicensed.)

Figure 5.3 Number of 15-19 year old drivers involved in crashes who had alcohol recorded as a factor, 1994-2003

The increase in the number of 15-19 year old drivers involved in crashes after 2001 may have occurred because young people had increased access to alcohol after the purchase age was lowered.

5.4 Summary

The three traffic indicators - percentage of drivers under 20 exceeding their legal breath alcohol limit, prosecutions for driving with excess alcohol, and numbers of drivers involved in crashes who had alcohol recorded as a factor - show different trends. One of the indicators shows no increase in young drink-drivers after the purchase age was lowered. But the other two indicators show increases in young drink-drivers after the purchase age was lowered.

Between 1997 and 2004, 1% to 3% of those under 20 years old who were stopped at the roadside had excess alcohol readings. Because of the relatively small numbers of those under 20 years old in the sample each year, there can be quite large fluctuations from year to year.

In 2004 the number of young people prosecuted for driving with excess alcohol was the highest recorded in the decade. After the law change, these people made up a slightly higher proportion of all the drivers prosecuted for driving with excess alcohol. This increase may have been influenced by changes other than lowering the purchase age which may have made it easier to prosecute young people for this offence. It is not possible to quantify how much of the increase can be attributed to lowering the purchase age; however, it is likely that some of the increase can be attributed to young people having increased access to alcohol after the purchase age was lowered.

Both the number and the percentage of 15-19 year old drivers involved in crashes who had alcohol recorded as a factor that contributed to the crash decreased between 1994 and 1999. Following the law change, the number and percentage continued to decrease in 2000. The numbers increased slightly each year between 2001 and 2003, although the 2003 figures were still much lower than the figures in 1994 and 1995. Between 2001 and 2003 the percentages fluctuated at a lower level than the level between 1994 and 1995. The decrease may have been influenced by activities designed to target drink-drivers. The increase in the numbers from 2001 may have occurred because young people had increased access to alcohol after the purchase age was lowered.

Footnotes

10 Apprehension data for traffic offending is not available.

11 Most of the offences classified as driving with excess breath or blood alcohol are imprisonable.

12 The two changes to the licensing procedure were photo driver licences and the mandatory production of driver licences. The photo driver licence upgrade took place over a 14 month period from 3 May 1999 to early July 2000. By 1 December 1999, approximately half of the driving population would have upgraded their licences. From 3 May 1999, drivers were required to produce immediately their driver licence for inspection at the request of an enforcement officer.