Thousands of drink drivers are blowing positive blood alcohol concentration samples into their fitted alcohol interlock devices every month. Drink-driving accounts for 15-20 per cent of road fatalities and 15 per cent of serious injuries each year in Victoria, says VicRoads.

Latest data from Victoria Police suggests overall less people are getting behind the wheel drunk. The number of people who returned a positive result from a preliminary breath test in Ballarat has dropped significantly since 2014. Victoria Police has not released how many people were breath-tested each year. 

Between 2014-15 116 people in the Ballarat policing area returned a reading up to 0.15. Between 2015-16 that number dropped significantly to 85. 

Bendigo police noted a similar drop from 118 in 2014-15 down to 67 while Geelong police saw a drop from 461 to 332.

Across the board police tended to see a greater drop in the number of lower range drink drivers detected. In Ballarat 31 drivers with a range up to 0.15 were apprehended in 2014-15 down to 18 the following year. Bendigo results dropped from 46 to 16 while Geelong results dropped from 227 to 180. An alcohol interlock is an electronic breath testing device that prevents a vehicle from starting if it detects alcohol.

The alcohol interlock will also ask for breath tests during the trip. It records all breath tests requested and any attempts to drive with alcohol present on your breath.

In 2016 the state government launched an extended alcohol interlock program. Currently, interlock devices are only mandatory for full-licence offenders with a BAC of 0.07 or more,repeat offenders and those on a probationary licence or learner permit.

When new legislation is tabled anyone found to be driving with a BAC over 0.05 will be required to drive vehicles fitted with an alcohol interlock device for a specified period, depending on the severity of the offence.

Currently, most full-licence holders caught with a BAC reading of between 0.05 and 0.07 will receive a fine and lose 10 demerit points.

Roads and Roads Safety Minister Luke Donnellan said the tougher restrictions would act as deterrent and remind drink drivers they would be held responsible for their actions.

“Disturbingly, around 20 per cent of drink drivers are repeat offenders,” Mr Donnellan said.

“Fines and demerit points alone aren’t working – more is needed to help reduce the number of Victorians who lose their lives or are seriously injured on our roads every year because of drink driving.”

VicRoads director of vehicle and road user access Robyn Seymour said programs were aimed to “help keep Victorians safe from drink-drivers, with alcohol interlocks proven effective in helping to prevent drink-driving from occurring”.

“Interlock violations happen for a number of different reasons and while the number of violations occurring each month is high, each violation means that a drink driving offence has been prevented, keeping more Victorians safe on our roads,” said Ms Seymour.

“We know that alcohol and driving don’t mix and we want all Victorians to be safe on the road. Drink driving accounts for 15-20 per cent of road fatalities and 15 per cent of serious injuries each year in Victoria, and educating people about the dangers associated with drink-driving is just as important for changing driver behaviour.” 

VicRoads has data available from just January 30, 2015 on the number of installations of approved alcohol interlock devices. 

In the Victorian Alcohol Interlock Program, there are VicRoads managed drivers and court managed drivers. VicRoads estimates that for VicRoads managed drivers the average length of an interlock installation is between six and nine months and for court managed drivers between 12 months and two years.

Drink-driving laws set a minimum time period for alcohol interlock installation based on the offence; when an interlock can be removed depends on whether there are violations and whether the drink driver has used the vehicle with the interlock consistently or not. 

In October 2014, new laws were introduced in Victoria requiring drivers with an alcohol interlock condition on their licence to have five months violation-free before they can have their interlock condition removed.

Since the changes were introduced, there has been a downward trend in the number of violations.

Drink drivers who have an interlock condition and an interlock installed in any vehicle they drive will not be caught driving with a positive BAC reading as the interlock prevents this.

If a drink driver drives a vehicle without an interlock and with a positive BAC reading they have committed two offences and the penalties are severe.

Drink drivers may be able to tamper with an alcohol interlock to circumvent this. Tampering will be detected by the service agents and again penalties are severe, however it is estimated that tampering is the cause of only 1-2 violations per month.

The TAC has shifted its message slightly to try and break any association between drinking and driving. Road safety manager Samantha Cockfield said most Victorians understand the consequences of drink driving but said some drivers continued to flout the laws and put themselves at others at grave risk.

“There is still a minority who do the wrong thing and put other people's lives at risk because they choose to drink and drive,” Ms Cockfield said. Research shows drivers with a blood-alcohol level of 0.05 are twice as likely to have a crash than before they started drinking.

“We want everyone to think about how they can make good decisions on the roads and get home to their loved ones safely. The easiest way is to separate drinking from driving altogether.”