New Zealand Police: Enforcing drink-driving laws

Progress in responding to the Auditor-General's recommendation.

Introduction and context for this progress report

Effective road policing can save many lives every year, reduce the number and extent of injuries to road users, and improve the efficiency and reliability of travel on New Zealand roads.

In February 2013, we published a performance audit report about one aspect of road policing. New Zealand Police: Enforcing drink-driving laws looked at how effectively and efficiently the New Zealand Police enforced drink-driving laws. This article provides a “snapshot” of the progress the Police have made in implementing the recommendation we made in that report.

Our 2013 findings and recommendation

Our 2013 report focused on the Police’s effectiveness in enforcing drink-driving laws but also commented on efficiency. We acknowledged that assessing effectiveness and efficiency is complex because the Police’s work is part of a system of factors that affect road safety.1

We found that, when considered together, trends in breath-testing and indicators of reduced alcohol-impaired driving suggested that the Police’s enforcement work has had a positive effect. However, we could not form a view on whether the Police are as effective as they could be because the available information was inadequate.

We found that the Police needed to improve how they assess and report on how effectively and efficiently they enforce drink-driving laws.

We recommended that the Police decide on a consistent and clear set of national indicators and:

  • monitor those indicators consistently over time to better understand results and identify where they can make gains;
  • use the understanding this gives them to enforce drink-driving laws more effectively and efficiently; and
  • use those indicators to report publicly and consistently on how effectively and efficiently they enforce drink-driving laws over time.

The Police accepted our recommendation and reported that they had begun working with the New Zealand Transport Agency (NZTA) to improve how they would monitor and report on their effectiveness. They noted a greater focus on outcomes.

Summary of progress since 2013

The Police have taken some important steps to improve their assessment of the effectiveness of how they enforce drink-driving laws. The Police have further work to do to fully implement these improvements, and we encourage them to see the improvements through.

Fully implementing these improvements should put the Police in a good position to:

  • better understand their effectiveness and efficiency;
  • use this understanding to inform their activities; and
  • report publicly on their performance in enforcing drink-driving laws more clearly and consistently.

The Police have also made other procedural improvements. These include introducing new equipment to enhance the effectiveness and efficiency of breath testing and processing of offenders.

Improving assessment of the effectiveness and efficiency of road policing activities

Intervention Logic for Road Policing

In March 2015, as part of the 2012-15 Road Policing Programme2, the Police introduced the Intervention Logic for Road Policing (ILRP), which the Police expect will, among other things, enable them to decide the most effective and efficient strategies for enforcing drink-driving laws. The objectives of the ILRP are to:

  • improve the transparency and consistency of the Police’s decision-making about road policing activities;
  • identify which activities are supported by evidence;
  • identify the conditions and characteristics that enable activities to be delivered effectively and cost-efficiently; and
  • support the continuous review of road policing activities.

The ILRP provides an evidence-based platform to inform the most effective and efficient strategies for enforcing drink-driving laws. It supports most existing strategies and provides a sound basis for informing those new to road policing on best practice.

It is too soon to assess whether the ILRP is meeting its objectives. The Police need to do further work to determine how they will evaluate the effectiveness of road policing activities and how they will apply what they have learned from those evaluations.

A broader range of indicators to understand performance

The Police use a range of indicators to assess and report on the effectiveness of how they enforce drink-driving laws. These include activity volumes they report to the Ministers of Police and Transport in Road Policing Quarterly Reports and performance measures for alcohol-impaired driving in the National Land Transport Fund Annual Report.

In a January 2015 internal briefing on the effectiveness of breath testing, the Police reported against the following indicators:

  • drink-driving offences;
  • injury and non-injury crashes with alcohol as a factor;
  • convictions; and
  • the number of breath tests.

These indicators showed a trend of an increasing number of breath tests for each detected drink-driving offence and a trend of fewer alcohol-related crashes. The Police concluded that these trends indicate a trend of less drink driving. Although they acknowledge that other factors have influenced these trends, such as advertising and changes in societal acceptance of drink driving, the Police consider that enforcing drink-driving laws is a contributing factor.

In our view, using a range of indicators to understand possible links between the Police’s main activities in enforcing drink-driving laws (in this instance, breath tests) and the effect those activities have on the prevalence of drink-driving and its consequences is encouraging.

Further work to do to report publicly against national indicators

1.18 The Police acknowledge that their public reporting on the effectiveness and efficiency of how they enforce drink-driving laws has not advanced significantly since we completed our performance audit in 2013. The Police do not yet report publicly against a set of national indicators that provide a coherent and clear picture of how effectively and efficiently they enforce drink-driving laws.

Procedural and equipment improvements

New legislation came into effect on 1 December 2014 that lowered the adult (over 20 years old) breath-alcohol limit from 400 micrograms to 250 micrograms of alcohol for each litre of breath, and an equivalent reduction in the blood alcohol limit.

After the new legislation came into force, the Police updated and streamlined the evidential testing procedures and forms for recording them, and prepared to introduce new breath-testing technology in 2015. The Police also introduced electronic fingerprint scanning in “booze buses” to improve their processing of offenders and to identify false information from repeat drink-drivers.

The Police introduced training programmes for all frontline officers and guidance materials reflecting these changes.

In our view, the processes now in place appear more streamlined than those in place in 2013. If carried out properly, the new processes should reduce the risk of records being lost and provide greater accuracy and timely completion of breath-testing and blood-testing procedures.

In May 2015, the Police announced that they would be introducing new hand-held breath-testing devices. The new devices will replace the existing hand-held breath-testing devices over time, with the first 400 devices to be rolled out shortly. The new devices are able to:

  • conduct evidential breath tests at the roadside ‒ this is expected to save time and cost because officers will not need to transport suspects to Police stations or “booze buses” for evidential breath tests; and
  • capture data from the devices, including the identity of the administering officer, the differences between the outcomes of passive breath screening and evidential breath tests, and the location of tests ‒ this is expected to inform evaluations of the effectiveness of the Police’s strategies to improve drink-driving trends and to inform operational and strategic decisions about targeting activities against assessed risk.

We will continue to monitor the progress the Police make to improve how they assess and report on how effectively and efficiently they enforce drink-driving laws. In particular, we will monitor whether they report publicly against a set of national indicators that provide a coherent and clear picture of how effectively and efficiently they enforce drink-driving laws.

1: For more information about this system of factors, see Safer Journeys: New Zealand’s road safety strategy 2010-2020 at

2: The 2012-15 Road Policing Programme was prepared by the NZTA and approved by the Minister of Transport in consultation with the Minister of Police ‒ see