Part 1: Introduction

New Zealand Police: Enforcing drink-driving laws.

In this Part, we discuss:

  • the purpose of our audit;
  • what we audited;
  • what we did not audit; and
  • how we carried out our audit.

The purpose of our audit

We carried out a performance audit to assess how effectively the New Zealand Police (the Police) enforce drink-driving laws.

The Land Transport Act 1998, which sets out New Zealand's drink-driving laws, allows the Police to stop and test the breath of anyone driving or trying to drive a motor vehicle on a road.

A driver who is 20 years or older commits an offence if they drive with an alcohol level exceeding 400 micrograms (mcg) for every litre of breath or 80 milligrams (mg) for every 100 millilitres (ml) of blood (a blood-alcohol concentration above 0.08). Drivers under the age of 20 are not allowed to have any alcohol in their blood. In this report, "drink-driving" means exceeding these legal limits.

Drink-driving and driving too fast for the conditions are the two main causes of serious road crashes. Drink-driving contributed to about 38% and speeding to about 35% of New Zealand's 2010 road toll.1 The road toll includes drivers, their passengers, people travelling in other vehicles, cyclists, and pedestrians.

Drink-driving and speeding concern New Zealanders. In 2011, New Zealanders rated alcohol and excessive speed as the two major road safety problems.2

During the 1990s, substantial progress was made in reducing the number of drink-driving and speed-related deaths. As a result, the road toll reduced significantly. Since 2001, the number of deaths that speeding causes has continued to decrease, albeit at a slower rate from 141 in 2001 to 131 in 2010. Conversely, the number of deaths that alcohol-impaired drivers cause has increased from 115 in 2001 to 142 in 2010.

We focused on drink-driving in this audit because we wanted to know why there had not been a reduction in the number of alcohol-related deaths since 2001. When we selected this topic, the percentage of total road deaths where alcohol was a contributing factor was increasing. The 2011 road toll figures have since been released, and both the road toll and the number of alcohol-related road deaths have decreased significantly. It is too soon to tell whether the road toll will remain low.

The cost of drink-driving is high. In 2010, drink-driving resulted in 142 deaths, 552 serious injuries, and 1559 minor injuries. The estimated social cost was $898 million.3 Between 2001 and 2010, drink-driving killed more than 1250 people and injured more than 21,000.

Males and drivers aged under 25 are more likely to drink then drive and crash than other drivers. In 2010, 76% of drink-driving offenders were male. Between 2008 and 2010, 83% of drivers involved in fatal alcohol-related and drug-related crashes were male.

Young drivers are also over-represented in drink-driving statistics. In 2011, 49% of drivers at fault in alcohol-related crashes were under the age of 25. Research shows that younger drivers who drink and drive are more likely to crash than older drivers who drink and drive.

Appendix 1 has background information on the profile of drivers who drink then drive, when people drink then drive, and the profile of those who die in alcohol-related crashes. Appendix 2 has information about the known effects of different blood-alcohol concentrations and the predictable effects on driving. Appendix 3 has information on drink-driving laws and a summary of court-imposed penalties for alcohol offences.

Safer Journeys

The Government has produced a strategy to guide road safety between 2010 and 2020 (Safer Journeys: New Zealand's road safety strategy 2010-2020). The strategy recognises that New Zealand needs a safe-system approach to road safety to make real progress in reducing the number of road deaths and serious injuries.

The safe-system approach acknowledges that:

  • people make mistakes and crashes are inevitable;
  • the body has limited ability to withstand crash forces;
  • system designers and system users must share responsibility for managing crash forces to a level that does not result in death or serious injury; and
  • it will take a system-wide approach – safe roads and roadsides, vehicles, speeds, and road users – to improve road safety.

The National Road Safety Committee, which is responsible for the Safer Journeys strategy, includes representatives of the Ministry of Transport, New Zealand Transport Agency, the Police, Accident Compensation Corporation, and Local Government New Zealand. Associate members include representatives of the Department of Labour (now part of the Ministry of Business, Innovation and Employment), the Ministry of Education, the Ministry of Health, and the Ministry of Justice. Regional and local road safety partners (regional transport committees and local authorities) play a role in implementing Safer Journeys.

Safer Journeys identifies 13 "priority areas", including reducing the incidence of alcohol- and drug-impaired driving. Within this priority area, the Police are responsible for enforcing drink-driving laws. The Police also consider the "fatal five" (speeding, drink or drugged driving, restraints, dangerous or careless driving, and high-risk drivers) as priority areas that are closely in line with Safer Journeys and the Road Policing Programme.4

What we audited

We audited how effectively the Police enforce drink-driving laws using general deterrence and targeted enforcement. We chose to audit the Police because international research shows that enforcement is the main deterrent to drink-driving. Although our audit focused on effectiveness, we comment, when appropriate, on how efficiently the Police work.

The New Zealand Transport Agency administers the National Land Transport Fund, which funds enforcement activities. In 2011/12, the budgeted amount for road policing was $297 million, which is about 20% of the Police's total funding of $1,480 million. We looked specifically at the $67 million (23%) of the road policing budget that was allocated to enforcing drink-driving (and drug-driving) laws in 2011/12. We focused on enforcement strategies, how the Police carried out operations, and the monitoring and reporting of drink-driving law enforcement.

The Road Policing Programme for 2011/12 sets out the desired results to which the Police are expected to contribute and estimates the demand and resources needed. It estimated that the Police needed to carry out 2.7 million breath tests using about 470-485 staff. In this report, we often refer to the number of breath tests completed. We count breath-tests by adding the number of passive breath tests (when a "sniffer" device is used to detect alcohol) and breath-screening tests (used to work out whether the breath alcohol level is above or below the legal limit) that Police officers complete at checkpoints (compulsory breath-testing, or CBT) and by officers on patrol (mobile breath-testing, or MBT).

We found it difficult to audit this topic. Some of the statistics we refer to (for example, road crash statistics) combine the number of crashes to which alcohol contributed with the number of crashes where drug use was a factor. Safer Journeys and the Road Policing Programme refer to "alcohol/drug impaired driving". At times, we had to refer to alcohol and drugs because it would have been inaccurate to refer to alcohol only.

Another complexity relates to collecting, collating, and reporting information. Most road safety results (road crashes, injuries, and fatalities caused by road crashes) are reported by calendar year. The Police plan and report what they do to enforce drink-driving laws by financial year. This means that sometimes the data sets in our analysis were not completely in line. We indicate where this happens. In parts of this report, we have referred to 2012 road toll figures. However, because of the timing of publication, we were not always able to provide a full analysis of 2012 road toll figures and had to use 2011 statistics.

What we did not audit

We did not audit:

  • the effectiveness of activities to reduce the effect of alcohol-impaired driving that the Police do not carry out (such as education programmes, advertising campaigns, and engineering activities5);
  • the Road Policing Programme and funding model or the non-alcohol-related priorities in Safer Journeys and the Road Policing Programme;
  • the enforcement of laws against driving while drugged, because drugged-driving laws date from 2009 and there is not enough prosecution data to show trends; or
  • enforcement targeted at recidivist drink drivers (drivers with three or more drink-driving offences), because research shows that enforcement strategies are unlikely to have a significant effect on high-risk or recidivist drink drivers.

We have not formed a view on any aspects of drink-driving laws or policy because doing so is outside the Auditor-General's mandate.

How we carried out our audit

We visited four of the 12 Police Districts, choosing a mix of metropolitan, provincial, and rural areas. We observed booze bus operations and we accompanied officers in patrol cars who stopped and breath-tested drivers. We watched drink-drivers being processed in booze buses and at police stations.

We interviewed and got documents from Police National Headquarters staff who manage road policing and enforcing drink-driving laws. We interviewed staff and reviewed documents from entities that the Police work with on road safety. The interviewees included representatives from the Ministry of Transport, New Zealand Transport Agency, Accident Compensation Corporation, local authorities, and the National Road Safety Committee. We met with relevant staff to help us interpret the documents or data and to answer our questions.

We examined many documents relevant to drink-driving aspects of the Police's operations, including:

  • policy manuals and strategic documents;
  • national and international research on enforcing drink-driving laws;
  • internal and external performance reports;
  • training manuals;
  • asset management plans; and
  • accountability documents, financial statements, and costing reports.

1: Some drink-driving statistics include drugged driving. We were not always able to isolate figures for drink-driving. We were told that the figures for drugged driving are low enough that they do not distort the statistics.

2: Ministry of Transport (2011), Survey of public attitudes to road safety, available at

3: The social cost of road crashes includes not only the loss of life, but also lost quality of life, lost productivity, and medical, legal, and property damage costs.

4: The Road Policing Programme sets out what the Police will do, the funding for their activities, and the performance measures used (see the New Zealand Transport Agency website,

5: Engineering activities include designing and building median barriers, rumble strips, and guard rails; putting in place line markings, electronic warning devices, and road shoulders to create forgiving roadsides; and applying skid-resistant surfaces.

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