San Francisco  - Californians convicted of drunk driving will be required to install electronic breathalyzer devices that prevent their cars from starting if they have consumed alcohol.

The measure was signed into law by California Governor Arnold Schwarzenegger and will initially take effect in a pilot scheme to be introduced in four counties.

The so-called ignition interlock devices will keep cars from starting if the driver's breath shows more than a small amount of alcohol.

"We must do everything we can to ensure the public's safety on the road," Schwarzenegger said after signing the bill. "By installing ignition interlock devices, we are making it harder for DUI offenders to get behind the wheel while intoxicated, and we are working to save innocent lives."

California reported 1,355 drunk driving fatalities last year. An estimated 550 drunk drivers are arrested every day. (dpa)