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ESR: Health, PO Box 50-348, Porirua, New Zealand
In 1991, 166 drinking drivers with blood alcohol levels in excess of the legal limit (80 mg/100 ml) were involved in fatal road accidents in New Zealand. Ninety-three percent of these had either blood alcohol levels over 150 mg/100 ml, were in the age group of 18-28, had a prior conviction for drink driving, dangerous driving, driving while disqualified or violence, or were currently disqualified at the time of the fatal accident.
The characteristics of this hard core group will be examined and compared with those of sober drivers in fatal accidents. Those of the drinking drivers with a prior conviction for drink driving will be compared with the drinking drivers who did not have such a prior conviction. The former are older, more likely to be males, to be unemployed, to have convictions for dangerous driving, careless driving, driving while disqualified or violence, or involvement in prior reported injury accidents.
The incident of recidivism will be compared with drivers in injury accidents and with drivers apprehended by the police. The impact of Compulsory Breath Testing on the hard core group will be discussed.
The dominant factor in serious injury road accidents in most Western countries is the excessive consumption of alcohol. Recently there has been a reduction in the proportion of the road toll associated with alcohol, in USA, Canada, Australia and Europe [Wilson, 1993]. New Zealand has not experienced this reduction [Bailey, 1994]. There has been a developing awareness overseas that there remains a large proportion of drinking drivers in fatal accidents who come from a "hard core" [Wilson, 1993]. This is associated with high blood alcohol levels and prior offending patterns. The group is resistant to conventional methods aimed at reducing drinking and driving. As the social drinkers are deterred from drinking and driving, the hard core increasingly dominates drink driving statistics.
Bailey  has shown that this hard core group dominated fatal drink driving accidents in New Zealand in 1986. If the hard core group is defined as including drinking drivers who either have blood alcohol levels over 150 mg/100 ml or have a prior conviction for drinking and driving, dangerous driving, or driving while disqualified, then about three quarters of drinking drivers came from the hard core in 1991-1992. Similar proportions of drinking drivers who were found to be over the legal limit in reported injury accidents, or drivers convicted of drinking and driving after apprehension by the Police, were found to be in this high risk group.
A number of countermeasures have been introduced to minimise drink driving. None of these has been specifically aimed at the hard core; none of them has been particularly effective. Bailey [unpublished data] has found that Compulsory Breath Testing (CBT), introduced in New Zealand on 1 April 1993, has proved as effective in reducing the number of drinking drivers with high blood alcohol levels as in those with levels in the range 81-150 mg/100 ml.
New initiatives against hard core drinking drivers are required. In planning and evaluating these, information is required about the hard core. This study considers three alternative definitions of hard core drinking drivers:
The last is based on a Parliamentary Bill permitting the confiscation of the vehicles of certain serious traffic offenders with a prior conviction for drink driving, dangerous driving or driving while disqualified.
Data from official accident reports, postmortem and hospital blood samples, breath test reports, Coroners' reports, and court records were matched by name and date of birth, death or accident, for all fatal road accidents in New Zealand in the years 1991-1993. The number and characteristics of hard core drinking drivers were determined by studying fatal accidents in the years 1991-1992. These are compared with those for the year 1993, to determine the impact of CBT on the hard core.
The proportion of drivers who had previously been involved as a driver in a reported injury accident was determined by locating drivers in reported injury accidents in 1981-1993 who had almost identical names and dates of birth.
Blood alcohol data were available for 70.5% of the drivers fatally injured in 1991-1992, but for only 20.0% of the surviving drivers. Of those drivers suspected by the police of being drinking drivers, blood alcohol levels were available for 86.3% of the fatally injured drivers and 70.5% of the surviving drivers.
Table 1 shows the proportion of the 315 drinking drivers, with BACs over the legal limit of 80 mg/100 ml, involved in fatal accidents in 1991 and 1992, who met each of the three definitions, and their characteristics relative to the drinking drivers who were not defined as hard core drivers. The Table also gives the corresponding characteristics of the 491 sober drivers in the fatal accidents who were considered to be at fault in the accidents.
Characteristics of Groups of Drivers Involved in Fatal Accidents
|Hard Core Definition||1: High BAC||2: Drink driving recidivist||3: Prior offenders or high bac||Sober|
|% aged 15-19||12||20||4||22||12||24||14|
|% aged 20-24||33||32||33||32||33||32||19|
|% aged 25-34||34||33||39||30||34||33||19|
|% aged 35-44||17||7||20||10||17||2||17|
|% aged 45+||4||8||4||6||4||9||31|
|% prior injury accidents||17||14||26||10||19||7||10|
|% prior DD convictions||43||29||100||0||51||0||10|
|% prior DA convictions||9||8||15||5||12||0||6|
|% prior CD convictions||22||15||35||10||22||11||11|
|% prior DWD convictions||18||10||35||3||20||0||3|
Definition (2) yields the smallest percentage (38%) of hard core drivers; definition (3) yields the largest number.
All three definitions include appreciably smaller percentages of teenagers in the hard core group than the remaining drinking drivers, with correspondingly higher proportions of drivers aged 35-44. A higher proportion of the hard core groups were unemployed than for the remainder; unemployed drivers have a high rate of involvement in fatal drink driving accidents in New Zealand.
For the two definitions involving consideration of prior offending, the proportion of the hard core drivers involved in a prior injury accidents is about two and a half times greater than for the remaining drivers.
Definition (1) separates drivers by whether or not they have prior convictions for drink driving, dangerous driving or driving while disqualified. Definition (2), which separates only by whether prior offenders for drinking and driving, gives clear distinctions in terms of convictions for dangerous driving, careless driving and driving while disqualified. Definition (3), based on a division by BAC, does not so clearly distinguish between records of prior offences. In particular, drivers with high BACs have rates of drink driving recidivism only slightly greater than those for drivers slightly over the legal limit. The percentages of drivers with a prior careless driving conviction are similar for the non hard core drinking drivers and the sober drivers at fault in fatal accidents.
Table 2 shows the outcome of court sentences on drinking drivers classified as hard core or not, according to definition (3) and on sober drivers at fault, in fatal accidents.
Convictions for Hard Core, Non Hard Core and Sober Drivers Involved in Fatal Accidents in 1991-1992
|Group of drivers:||Hard core, drinking||Drinking, non-hard core||Sober at fault|
|of convicted, % imprisoned||76||70||5|
|mean prison term (days)||778||389||506|
|mean disqualification (days)||1093||768||580|
|% with prior criminal conviction||53||36||20|
|mean no. criminal convictions||11.1||4.1||8.2|
|% with prior traffic conviction||74||54||42|
|mean no. traffic convictions||5.1||2.0||3.1|
Comparison of analyses for 1993 with those for 1991-92 shows that for both the hard core drivers and the remainder, the reductions in numbers were less for the unemployed, those living in rural areas, those with prior convictions for dangerous driving or driving while disqualified, or those with large numbers of prior criminal or traffic convictions.
The courts gave much harsher sentences to those drinking drivers in fatal accidents identified as hard core by definition (3). Both hard core and non hard core drinking drivers received harsher sentences than the sober drivers, apart from the longer average prison term for the sober drivers relative to the non hard core drinking drivers. This is based on a small number of drivers, most of whom were convicted of dangerous driving causing death which often carries a long prison sentence. All of the drivers who were convicted of manslaughter (which carries the longest prison terms) were from the hard core group. Drivers in the hard core group received terms of imprisonment about double those of the non hard core drinking drivers, and terms of disqualification about half as long again.
A higher proportion of the hard core drivers had a prior traffic or criminal conviction; of those that had such a conviction, the mean number of convictions was two and a half times greater for the hard core offenders than the non hard core.
The introduction of CBT in 1993 has had less impact on certain groups of high risk drivers such as the unemployed or those living in rural areas and on those with large numbers of prior traffic or criminal convictions, particularly those for dangerous driving or driving while disqualified. The drinking drivers involved in fatal accidents in 1993 had a larger number of prior drink driving convictions per driver. These observations provide some urgency to develop alternative or supplementary ways of handling certain types of drinking drivers such as the hard core drivers discussed here to those offered through methods such as CBT.
The most desirable definition of a hard core offender is that which focuses on those drinking drivers who come from the groups with the highest risk of accident. This includes drivers with high previous involvement in injury accidents, drivers with high BACs which are associated with a high risk of accident, young drivers (particular those aged 20-24, who have a high accident rate) or drivers with certain patterns of prior offending. Often these factors overlap.
The third definition, based on the proposed Bill for confiscation of certain offenders' vehicles, is the most comprehensive definition. If emphasis could be placed on this hard core group of offenders through enforcement, education, publicity, rehabilitation and the courts, a moderate reduction in the number of such offenders could lead to a sizable reduction in deaths and injuries, since these drivers have an appreciably higher risk of accident than other drink drivers and, more so, the non-drink driving public.
A hard core of drinking drivers can be identified. A definition based on both high blood alcohol levels and prior offending patterns covers many of the high risk groups. The New Zealand Parliament is presently considering a Bill allowing the confiscation of certain traffic offenders' vehicles, which focuses on some aspects of the hard core group defined here.
The author acknowledges the assistance of ESR: Forensic, Land Transport Safety Authority, the Police, Department of Justice and the Courts, in providing data.
Bailey JPM., 1993, "Criminal and Traffic Histories, Blood Alcohol and Accident Characteristics of Drivers in Fatal Road Accidents in New Zealand", EHFS Publication No. 3, Lower Hutt: Institute of Environmental Health and Forensic Sciences Ltd
Bailey, JPM, 1994, "Fatal Road Accidents Involving Alcohol in New Zealand During 1987-1992", ESR Publication. Series no. 13, Environmental Sciences & Research Ltd, Porirua
Wilson, RJ, 1993, "Drinking and Driving: in Search of Solutions to an International Problem", Alcohol Health & Research World, 17 (3), 212-220