Thousands of West Australians will have breath-testing immobilisers fitted to their cars under a State Government plan to cut the drink-driving death toll.
The alcohol interlock system would be fitted to cars driven by anyone caught with a blood alcohol concentration of 0.15, anyone who had more than one 0.05 offence in five years and anyone who refused a breath test.
There were about 2000 people caught above 0.15 last year. The Government predicts another 2300 would be caught for being over 0.05 for at least the second time.
Drivers would have to blow into a tube fitted to their car's ignition system, which would work only if they registered under 0.02.
To prevent drink-drivers getting friends to blow for them, the system would be calibrated to need another breath test at random intervals during the journey. Failure to provide the second sample could trigger hazard lights or horns to attract attention of other drivers or the police.
Every 28 days, drivers would have to submit their interlock system to the Department of Transport, which would download its memory.
This would show whether there had been attempts to tamper with the system or whether a driver had tried to drive with a blood alcohol level above 0.02. For many, this is less than one standard drink.
Those who had made three or more attempts to drive over 0.02 would be compelled to attend an alcohol intervention program to be run by the Drug and Alcohol Office.
Drivers will still have to pay fines and will have the interlock devices fitted for at least six months after serving their suspension. Extraordinary licences will be granted only if the interlock system is used.
It would also be compulsory for drivers whose licence had a zero-alcohol restriction such as heavy haulage, taxi or provisional drivers but who had been caught above 0.02.
If police catch a driver involved in the scheme driving a car not fitted with the device, the vehicle would be impounded for a minimum of 28 days.
Police Minister Liza Harvey said mandatory interlocks were shown to cut repeat drink- driving by about 64 per cent.
About 15,000 people were caught drink-driving in 2011-12 and she hoped legislation would be introduced in the second quarter of next year.
"We want to stop people from drink-driving and putting others at risk on the roads," Mrs Harvey said.
Drivers would have to rent the system for about $1600.
Simon Lenton, deputy director of the National Drug Research Institute, said alcohol ignition interlocks were one of the best deterrents for repeat drink-drivers who often flouted driving bans.
Road Safety Council chairman Murray Lampard said the devices would make WA roads safer.
"The use of these devices sends a very strong message that we will not tolerate this abhorrent behaviour," he said.