A Calvert County District Court judge is turning to technology to help keep drunk drivers off the road.

Since last month, Judge Larry D. Lamson has ordered 12 persons convicted of driving while intoxicated to have their cars equipped with a device that prevents the vehicle from starting if the operator is drunk. The devices, breath analyzers that connect to ignition systems, were recently marketed by a Denver company and were expected to be installed this week. Only a few jurisdictions in the country have tried them.

The small black boxes, equipped with long tubes, are installed underneath the dashboard. The driver must breathe into the tube for five seconds before the engine will start. If the meter on the box indicates a blood alcohol level of .05 percent or higher, the device will prevent the car's electrical system from completing the ignition circuit, and it will not start.

The device, made by Guardian Interlock Systems Inc. of Denver, costs about $350 to install and must be paid for by the offenders in Calvert.

Lamson said the equipment "is not foolproof" and is not "a cure-all or an easy solution to a very complex problem. It is just a little extra help that might work."

Lamson is the first judge in the Washington area to order the installation of the devices, which came to his attention at a judicial conference in January. "Anything that would keep a drunk person from driving is worth a try," he said.

He said the device is meant to augment, not replace, traditional sanctions against drunk drivers, such as weekend jail terms, community service and mandatory visits to alcohol treatment centers.

"This is brand new. We don't know how effective it will be. The only way to tell is to try it out," he said.

The only District Court judge in rural Calvert County, Lamson hears about 650 drunk-driving cases a year.

"We've tried all the routine things," he said. "We just haven't had much luck with keeping people off the highways when their licenses are suspended."

Part of the problem, Lamson said, is that public transportation is not readily available in Calvert County.

"People need to use their cars," he said. "The important thing is the device doesn't know if it is 7 a.m. and you are going to work or if it is in the evening. You still have to blow into the device to start the car."

The instruments are being used in Chicago and Denver, said Richard Freund of Guardian Interlock Systems. In addition, he said judges in Cincinnati are testing them, and the California legislature is considering a bill that would set up pilot programs in four counties.

Lamson said he is ordering that the devices be used by first offenders who had blood alcohol levels of .15 percent or higher at the time of arrest, and for repeat offenders who had levels of .08 percent or higher. In Maryland, motorists with a .13 percent alcohol level in their blood are considered to be driving while intoxicated; a level of .08 percent can lead to a charge of driving under the influence of alcohol.

All 12 persons ordered to install the device thus far have had blood alcohol levels of .15 percent or higher, Lamson said. The device must be in place for a year and must be inspected every 60 days, he said. Signs of tampering will be considered a violation of probation, with a penalty of 30 to 60 days in jail, he said.

Lamson, who appeared on CBS Morning News recently to discuss the device, said he has received a number of inquiries from parents of teen-agers. He said he has also received requests from business owners whose employes use company cars and drive them home at night.

He acknowledged that drivers could evade the device by having another person blow into the tube, but said he does not believe this is likely to occur.

"It is awfully hard to get a sober person to blow into a machine to let a drunk person drive," he said. "They are taking on some real liability if they do that."

Another way to evade the device is to drink after starting the car, Lamson said, but he added that he also considers that unlikely.

The benefits of the device outweigh the risks, he said. "Not only do you take the drunk driver off the road, but also, by having people use it for a year, they really have the opportunity to teach themselves what their limits are -- to change their drinking and driving habits."