A 23-year-old Australian man has been fined $500 as a result of being caught driving drunk. Christopher Petrie appeared in court on Monday, but a continuance was granted so that everybody could research the question whether the motorized beer cooler he was driving is considered a “motor vehicle” under applicable law.

The cooler, or “esky” as it is apparently called in Australian, was fitted with a 50cc engine and was one of two that Petrie and a friend bought on eBay. Petrie’s lawyer told the court that his client’s esky was “suffering some mechanical problems” on June 16, so he took it to his friend’s house and the two had a few drinks while fixing it. They then decided to take it for a “test drive,” where police saw them tootling along at 20 kilometers an hour (12 mph), and intercepted them after what was likely the least dramatic chase of the day. A breath test showed Petrie was over the limit (he registered 0.16), and a license check showed that he did not have a license. Charges followed.

Petrie’s lawyer claimed today that his client “didn’t realize the esky was classified as a motor vehicle,” which suggests that his research this week had concluded that it was. I’m not sure how the relevant statute is worded, but as we have seen before, the question (when it arises) is typically whether the drunk was driving a “vehicle,” or sometimes a “motor vehicle.” These definitions have been held sufficiently broad to cover DUI cases involving riding lawnmowers and motorized bar stools in addition to motorized beer coolers like the one at issue in Petrie’s case, and that seems to have been the result here too. (Whether a horse is a “vehicle” for DUI purposes is a tougher call, but is an issue for another day.)

This is not a foregone conclusion, as we saw in 2007 when a judge acquitted a Zamboni operator of drunk driving, holding that a Zamboni is not a “motor vehicle” under New Jersey law because it isn’t usable on highways and can’t carry passengers. Neither of those facts are true, of course, as we had seen the year before when two ice-rink employees in Boise were fired for taking their Zambonis through a Burger King drive-through. But apart from that outlier New Jersey decision, most non-automotive-motor-vehicle DUIs have been upheld, and Petrie was convicted as well.

Had there not been a mandatory minimum for violating the statute, Petrie might still have gotten off easy. While the magistrate said he did not “condone driving around drunk on an esky,” he also called it an “unusual” and even “unfortunate” situation. “If he’d been drunk on a horse he’d have been been OK,” the magistrate said (suggesting the law applies to “motor vehicles”), but “nevertheless you were in a motor vehicle … on a motor vehicle … and there must be a penalty.” Clearly, he was going to give Petrie the minimum, and he did. (At the arraignment, his only question for the defendant seems to have been “how much beer can it hold?”)

Personally, I think that devices not capable of a certain speed should not be “vehicles” for purposes of DUI laws, though I realize that’s debatable. Zambonis top out at less than 5 mph, and eskys can hit 13 mph with a strong tailwind. The danger level there seems pretty low. Given that the motorized bar stool mentioned above could allegedly reach 38 mph, though, it would definitely qualify. Awesome as it is, that’s just too much machine to drive drunk.