Judges have broad, almost unfettered discretion in sentencing, provided they remain with legislative and Constitutional guidelines -- punishments can't exceed statutory maximums or be "cruel and unusual." This would include, one assumes, ordering the imposition of an ignition interlock device; such an order neither increases incarceration beyond the maximum allowed by statute, nor constitutes a cruel and unusual punishment. Indeed, the problem this judge encountered was that she considered the cost of such a device part of the "fine" imposed on the defendant, and thus reduced the amount of the fine payable to the court -- a legal ruling which was overturned by a higher court, which happens to all judges from time to time.

Society is not harmed by a judge imposing a lawful, Constitutional, but nontraditional punishment. This is a case of a judge's real-world experience informing her rulings on the bench and causing her to come up with an innovative, smart, practical approach to recidivism. It is an imperfect approach, but the perfect should not be the enemy of the good.

In Maryland, the imposition of an ignition interlock device is done administratively. If you refuse to submit to a blood alcohol test, or if it is a second offense, your license is taken away in an administrative proceeding that is separate from the criminal proceeding. The only way to avoid the license suspension is to agree to an ignition interlock device. In my experience, that choice runs about 50-50 -- about half the people prefer to take the suspension, and half prefer to take the interlock device (which, as the judge pointed out, is rather expensive -- you pay for installation, and you also pay a monthly fee for the monitoring). If you are caught driving a non-interlock car, you're arrested -- it's the same as driving without a license, punishable by jail time even if you're stone sober. If you're caught having your child blow into the tube for you (which does happen), you're in big trouble, too; God help you when the judge hears that. But that is fairly rare for the simple reason that not only do you have to blow into the tube to start the car, but you have to blow into it periodically to keep the car running, and it's positioned such that it's hard for anyone other than the driver to reach it.

One last aside, relating to people who think that a single glass of wine won't trigger a DUI -- guess again. While you probably won't be impaired or notice any effects from a single drink, when the BAC limit was lowered to .08, it is entirely possible that one drink can put you over the limit without you knowing it.

(Want to stop drunk driving? Insane criminal penalties won't do it. Invest in mass transit.)