What is an alcolock?

Similar in appearance to the breathalysers police officers use on drivers at the side of the road, the alcolock is fitted to a vehicle’s ignition system, requiring a breath test before the engine can be started. 

To avoid cheating, the devices often require drivers to provide breath samples in certain ways which can involve humming or a suck-back breath pattern that have to be learned before use. In addition, they also require drivers to perform breath tests at random intervals during journeys. These random tests do not switch off vehicles while they are being driven, but missing or failing them can have consequences, which vary from country to country. 

Some haulage and coach companies have proactively fitted alcolocks to their vehicles to ensure their drivers are safe to be behind the wheel.  

Currently, courts in the UK cannot order convicted drink-drivers to have alcolocks fitted to their vehicles.  

The formal name for alcolocks is Breath Alcohol Ignition Interlock Devices, or alcohol interlocks. 

What countries use alcolocks? 

Here are the nations that currently use alcolocks for convicted drink-drivers: 

Europe 

• Belgium 
• Denmark 
• Finland 
• France 
• Italy 
• Lithuania 
• Poland 
• Sweden 

Around the world 

• United States 
• Canada 
• Australia 
• New Zealand 
• Japan 
• South Korea 
• Brazil 

How effective are alcolocks at preventing drink-drive reoffending? 

The use of alcolocks in Europe has been found effective at preventing habitual drink-drivers reoffending. 

The European Transport Safety Council reports that studies have repeatedly shown that alcolock programmes, combined with rehabilitation, reduce reoffending rates both during and after the driver has been required to have an ignition interlock device fitted to their vehicle.  

It states in its Alcohol Interlocks and Drink-driving Rehabilitation in the European Union report that traditional punishments do not seem to be effective for some repeat drink-drivers, and that this group accounts for 10% of all drink-driving offenders. It adds that reoffenders are involved in two-thirds of all crashes where alcohol is a factor. 

An alcolock programme in Finland carried out in 2013 found that, despite the low participation rate, alcohol interlocks used by the offenders had prevented at least 12,000 instances of driving while under the influence of alcohol. 

Separately, a New Zealand Ministry of Justice study of drink-driving sentences from 2013 to 2017 shows those given Alcohol Interlock Orders had 33% fewer drink-drive reconvictions and 40% fewer disqualified-driving convictions within four years compared to the non-AIO group. A New Zealand motoring group also reported that alcohol interlocks in the cars of high-risk drink-drivers stopped 37,061 attempts to use a vehicle in 2020. 

How does an alcohol interlock programme work? 

In New Zealand convicted drink-drivers are given an initial disqualification of 28 days or more. At the end of this they remain disqualified from driving until they have been issued with an ‘alcohol-interlock licence’. This only allows them to drive vehicles fitted with an alcolock which prevents the vehicle from being started if any alcohol is detected on offenders’ breath. 

During this time offenders are required to pay a fee for an interlock to be installed by one of three alcolock suppliers. For those who can’t afford this there is government assistance. They also have to pay a monthly lease fee to the installer. 

To leave the programme, offenders must have held their alcohol-interlock licence for at least 12 months and not had any alcohol detected in any of their tests in the last six months or committed any violations such as failing to do random tests, tampering with the device or trying to start the vehicle another way.  

However, if the offender’s alcohol interlock sentence replaces a previous indefinite disqualification that has not ended, they must not have committed any violations in the three-month period before they request to leave and have successfully completed a drug and alcohol assessment at a Ministry of Health-approved assessment centre. 

After being approved to exit, offenders have to apply for a zero-alcohol licence, and only then can the alcohol interlock be removed. After three years with no offences, they can apply for a standard licence again.  

What do drivers think of alcohol interlocks? 

More than half (53%) of drivers surveyed by the RAC in November 2024 said they believe alcohol interlocks would reduce instances of reoffending (24% unsure, 23% disagreed), while 66% were supportive of a scheme like those in other countries whereby offenders are banned for a short time, and then have to have an alcohol interlock fitted in order to keep driving. 

How bad is the problem of drink-driving in the UK? 

Drink-driving, along with drug-driving, is one of the so-called ‘fatal 4’ behaviours – the others being speeding, not wearing seatbelts, and mobile device use – that are the main causes of people being killed and seriously injured on the UK’s roads. Government estimates show that between 290 and 320 fatalities occurred in collisions in 2022 where at least one driver was over the legal alcohol limit (DfT, 2024).  

This represents 18% of all road deaths, second only to speed-related collisions which account for 56% of fatalities. This is the highest number of deaths due to drink-driving since 2009 and sadly takes the fatality rate from drink-driving back to the same level as the late 1980s. 

There were a total of 47,489 ‘driving a motor vehicle under the influence of drink or drugs’ offences in the year ending 2023. 

Reoffending is also a major problem. As many as 27,837 individuals were convicted of drink-driving offences multiple times in the 11 years leading to July 2024, a Freedom of Information request by the Press Association revealed.  

What is the RAC’s view on alcolocks? 

The RAC believes courts being given the power to order offenders to use alcolocks could in future reduce the number of drink-drive related collisions on the country's roads.