Driving under the influence of drugs is causing deaths and injuries on our roads, devastating families and communities. Brake strongly supports an increased focus on deterring, detecting and prosecuting drug driving.
Illegal drugs have a variety of very serious negative effects on driving ability, and the effects can be highly unpredictable given their unregulated and variable nature. Drugs affect different people in different ways and the effects can last for days, sometimes without that person being aware of it. The likely effects of some common illegal drugs on driving include:
- Cannabis slows reaction times, affects coordination and concentration and makes you drowsy. Research using driver simulators has found cannabis makes drivers less able to steer accurately and slower to react to another vehicle pulling out. 
- Methamphetamine makes people feel wide awake and excited, causing erratic behaviour and risk-taking; and can make people panicky. Users have difficulty sleeping, so will also be tired for days. 
- You may experience tiredness, anxiety and irritability as the effects of stimulants wear off, which affects the way you drive.
A study of fatal crashes in France between 2001 and 2003 concluded cannabis almost doubles the risk of being involved in a fatal crash. Analysis of road crash hospital admissions in Canada between 2009 and 2011 found cannabis use increases the risk of being involved in a serious crash by four times. 
The EU-commissioned "DRUID" research programme into the risks found fatal or serious injury crash risk increased by:
- 2 times for drivers on cannabis;
- 6 times for drivers on cannabis combined with alcohol;
- 2-10 times for drivers on cocaine or opiates;
- 5-30 times for drivers on amphetamines. 
Combining illegal drugs with alcohol increases risk: analysis of fatal crashes in the USA found drivers who have consumed both are 23 times more likely to be involved in a fatal crash than sober drivers. 
Many prescription and over-the-counter medications can also impair your ability to drive safely, for instance by causing drowsiness or affecting reactions times, coordination, concentration or vision. These include some cough and cold medicines, anti-inflammatories, anti-histamines, antibiotics, antidepressants, epilepsy drugs and sleeping pills. 
Brake would like to see New Zealand follow other jurisdictions such as England and Wales, Australia and some European states in changing the way it deals with drug driving.
There are limitations with the current CIT system in New Zealand, particularly the fact that a police officer has to have 'good cause to suspect' the driver is under the influence of drugs in order to test them. In addition, Brake is concerned that police are often unable to test drivers for drugs following a crash, because they are injured, in a state of shock or in emotional distress, and therefore unable to complete a CIT. The low number of CITs undertaken also means there is a limited deterrence effect for drug drivers.
Whilst there are limitations to oral screening devices, they provide a faster way to test drivers for the presence of drugs than the current CIT system, and whilst they can't test for all drugs, the existing devices available provide a good starting point.
In England and Wales, the law changed in March 2015, making it a criminal offence to drive with drugs in your body. The law set very low-level, effectively zero-tolerance limits for a range of illegal drugs. The law allows police to test and arrest for certain illegal and legal drugs, and removes the need to prove impairment, making it much easier to prosecute drug drivers.
The law is enforced with the aid of roadside screening devices. Those found guilty face a maximum six month jail sentence, £5,000 fine, and automatic 12-month driving ban.
The law also clarified the position for drivers using medication, with set limits for a number of prescribed drugs that can affect driving. These include drugs such as diazepam, morphine and methadone. Drivers taking medication in accordance with the advice of a healthcare professional are not at risk of arrest.
Since the implementation of the law there has been an 800% increase in arrests, despite limitations in testing equipment and levels of policing.
Brake would like to see the following measures implemented in New Zealand to address drug driving:
- Set very low-level, effectively zero tolerance, limits on illegal drugs.
- Set limits for prescription and over-the-counter medications that can impair driving.
- If a driver appears impaired, they are automatically tested for both alcohol and drugs.
- If a driver is hospitalised in a crash they are tested for drugs and prosecuted in accordance with the limits above.
- Use type-approved roadside testing devices to test for the presence of drugs, particularly focusing on cannabis and methamphetamine in the first instance.
- Introduce random roadside testing, with police given the power to test for drug driving without needing a cause to suspect impairment. Whilst it may not be possible to deliver random drug testing on the same scale as breath testing, a higher rate of drug testing will help to deter drug driving. It will enable police to test: drivers who have committed other offences and may be under the influence of drugs but are not visibly impaired; and drivers who have been involved in a crash but may not be fit to complete a CIT. It will also enable police to test drivers in other instances, and randomly at alcohol checkpoints or separate ones.
- The CIT system remains available to police for testing drivers that police suspect are impaired but return a negative result on alcohol/drug testing and may be otherwise impaired (by other types of drug or as a result of something else which makes them unfit to drive).
- Stepped up and targeted enforcement. Ensure police have funding, equipment and training to test and convict at effective levels, in order to take drug drivers off the road, and also deter others from driving under the influence.
- Use oral testing as a screening tool, and use blood testing as evidence of drug driving.
- Increase the penalties for drug driving offences, on a scale for first, second and third or more offences, but also engage with addiction support and other services to refer to and address underlying issues that drug users may be facing.
 Transport Research Laboratory, 2000, The Influence of Cannabis on Driving
 A-Z of drugs: Speed, Talk to Frank, undated
 British Medical Journal, 2005, Cannabis intoxication and fatal road crashes in France: population based case-control study
 University of Toronto, 2013, Cannabis and traffic collision risk
 EU DRUID Programme, 2012, DRUID Final Report: work performance, main results and recommendations
 Columbia University, 2013, Drug use and fatal motor vehicle crashes
 State of the road: medication and driving, Centre for Accident Research and Road Safety - Queensland, 2011