Richard Leotta holds a poster of his late son, Noah, in front of the statehouse to urge lawmakers to pass “Noah’s Law” on the last day of the Maryland state legislature on April 11 in Annapolis. (Bill O’Leary/The Washington Post)

A Maryland prosecutor said he hopes to expand the use of interlock devices to cover gaps in a new law that expanded their use.

John McCarthy, the Montgomery County state’s attorney, said this week that prosecutors in the Washington suburb will be asking judges to order the use of interlocks even in cases in which first-time offenders can avoid a conviction by agreeing to a term of probation.

What’s more, McCarthy said his prosecutors might go further — perhaps asking that judges order their use in cases where alcohol has not led to a DUI but has fueled criminal behavior, such as domestic violence.

“I like that idea,” McCarthy said in an interview this week. “I think it’s creative.”

Interlocks require a driver to blow into a Breathlyzer-like device before starting a vehicle. If alcohol is detected, the interlock prevents the vehicle from starting. Maryland’s General Assembly expanded their use this year. Among other things, the measure — known as Noah’s Law, in honor of a Montgomery County police officer who was killed by a drunk driver while working a DUI checkpoint in Rockville — requires first-time offenders to use interlocks upon their first conviction. The law took effect Oct. 1.

But about half of all first-time DUI offenders avoid convictions by receiving probation before judgment, a disposition known as a PBJ, McCarthy said. Under a PBJ, a person acknowledges guilt and agrees to serve probation on condition that the charges will not result in a final judgment or conviction.

“If you get a PBJ, the new statute doesn’t cover you,” McCarthy said. “And, I will tell you, in my county — and a lot of others — first offenders pretty routinely get PBJs.”

To close the gap, McCarthy has directed prosecutors to ask judges in most cases to order the use of interlocks with drivers who receive PBJs, at least for the term of probation.

“So what we want to do is to make sure that, despite the fact that the judge doesn’t have to order it, we want to make sure our people go into court and ask for that additional protection for the community,” McCarthy said.

But McCarthy also said the interlock could be useful in other scenarios besides DUI arrests. He said it might make sense, for example, for prosecutors to ask a judge to order the interlock’s use for a person who has a history of alcohol abuse and violence. Because a judge could order such a defendant to seek treatment for alcohol abuse as a condition of probation, the judge could perhaps order the installation of an interlock device, too. But the main focus will be on ensuring that people arrested on DUI charges don’t drink and drive.

Part of the reason his office wants to ensure their broadest possible application is because data have shown that interlocks are effective in keeping drunk drivers off the road, McCarthy said.

“This thing actually saves lives,” he said.

The Draeger Interlock XT, which prevents a vehicle from being started if the driver’s breath alcohol concentration is higher than the state’s limit. (Allison Shelley for The Washington Post)

A study by University of Michigan researchers estimated that installing interlocks in every new vehicle sold in the United States could cut drunken-driving fatalities by 85 percent over 15 years. The research, which was published last May in the American Journal of Public Health, also found that the financial benefits from installing the technology would outweigh costs within three years.

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