A new state law goes into effect today that officials hope will help reduce drunken driving.

People arrested for driving under the influence now can apply to use an ignition interlock device to legally continue to drive.

“It really reduces the likelihood of a repeat drunk driver running into you,” Washington State Patrol spokesman Robert Calkins said. “They can choose to continue drinking; they cannot continue drinking and driving.”

The interlock devices, hooked into the vehicle’s ignition system, requires a breath test before the engine will start. If the device detects alcohol, the vehicle will not start.

Use of the devices in Washington isn’t new, Calkins said. In the past, courts have been able to require convicted drunken drivers to use them.

With the new law, officials hope there will be more widespread use.

When people are arrested on suspicion of drunken driving they automatically lose their license — unless a judge later determines the person was innocent.

Still, people often need to drive to make a living, Calkins said.

“We know these folks are driving anyway,” he said. “They’re driving without a license, sneaking around.”

Some of them may want to continue to drive legally, he said.

Those people now can apply with the state Department of Licensing for a special interlock license. It costs $100.

The license is not available in cases where someone is charged with vehicular homicide or assault. Applicants also are excluded if they’ve been convicted of those crimes in the previous seven years.

People caught driving under the influence of drugs other than alcohol aren’t eligible. Proof of insurance is required.

Once someone obtains the ignition license, they must lease the device from one of several vendors, including Kent-based Affordable Ignition Interlock, which operates an installation and service center in Everett.

It costs about $75 a month plus a $20 monthly state fee, said Bryan Mooney, the company’s general manager.

Customers are required to have the device serviced at least once every two months, he said. That’s when the leasing company ensures the device is working properly and downloads a history of the recorded blood-alcohol levels for each attempt at starting the vehicle. Courts and other officials sometimes request these records.

“People are finding that there is no other deterrent to drunk driving that we know of today that’s as good as this one,” Mooney said.

Mouthwash and some other products that contain alcohol can give false readings, he said. Typically, people can rinse their mouth with water to clear the problem.

Seattle-based criminal defense attorney Patricia Fulton said the devices aren’t always reliable. She said she’s had several clients use them.

They sometimes malfunction and can drain car batteries.

“There are glitches with them,” she said.

Many of the devices require people to pass the breath test when the vehicle is started and again 10 minutes later. That’s meant to discourage people from finding someone else to blow into it to start the car, Calkins said.

Fulton said she’s never had a case where a client has been accused of tampering with an interlock device.

Washington’s law is modeled after a similar law in New Mexico, Calkins said. Statistics there show a reduction in drunken driving deaths since the law went into effect.

Drunken driving is the leading cause of traffic deaths in Washington.

“Why do people continue to drive drunk? Because they can,” said Judy Eakin, a spokeswoman for Mothers Against Drunk Driving, which supported the Washington law. “Ignition interlocks are a proven method of reducing the risk to society from impaired drivers.”

Reporter Jackson Holtz: 425-339-3437 or jholtz@heraldnet.com