There are a variety of defenses against charges of driving under the influence. We've shared storied before in this space about incidents where a drunk driving conviction was overturned or charges were dropped due to either the improper administration of a breathalyzer test or the improper calibration of the equipment that is supposed to measure a driver's blood alcohol concentration.

But a recent case raises another, albeit uncommon, defense to drunk driving charges. Forbes reports that a Zamboni driver was arrested this week for suspicion of driving while intoxicated. While this case is of course still making its way through the system it raises the question of DWI charges when the person is not driving a traditional vehicle. In a similar zamboni case several years ago, the New Jersey judge determined that a zamboni driver could not be convicted of driving under the influence.

In that case a zamboni operator in New Jersey was charged with drunk driving after he was reportedly driving his zamboni erratically at a sports arena. His blood alcohol content was allegedly 0.12, over the 0.8 limit. But the superior court judge overturned his conviction, penalties and license revocation. The judge explained that because the zamboni machines cannot carry passengers and cannot be driven on highways, they are not "motor vehicles" for the purposes of the drunk driving laws in New Jersey.

While the zamboni arrest is obviously a rather rare incident, this question can come up in other context such as boats and ATVs. It is important to remember, as this judge apparently did that in order to have a criminal conviction the prosecution must demonstrate that there has actually been a violation of the law as it is written.

Source: Forbes, "Do Drunk-Driving Laws Apply to Zamboni Drivers?" Kevin Underhill, Feb. 1, 2012