The increasingly expansive interpretation of drunk-driving laws around the country has applied the definition of "motor vehicle" to anything from horses and scooters to electric wheelchairs. While a Virginia lawnmower rider was arrested for driving under the influence (DUI), such charges may now be harder to file in Washington after the state Supreme Court last Thursday declared lawnmowers are not motor vehicles.

The justices were not deciding a DUI case last week. Instead, Joshua M. Barnes stood accused of a botched attempt at pilfering a gas-powered Craftsman lawnmower from a home in Leavenworth on June 22, 2015. In addition to theft and trespassing charges, prosecutors decided to raise the stakes from a class C felony to a class B felony by tacking on the additional charge of "theft of a motor vehicle." The high court agreed with Barnes that what he tried to steal was not, in the eyes of the law, a motor vehicle.

"Though a plain reading of the term could conceivably include a riding lawn mower, the legislature intended otherwise," Justice Susan Owens wrote for the majority.

Prosecutors had insisted that the additional charge was appropriate because the lawnmower was "self propelled" and "capable of being moved upon a public highway." Barnes countered by pointing out that the same could be said for golf carts, but the legislature excluded golf carts from the definition of a motor vehicle. He also pointed out that the prosectution's overly literal reading would mean a Roomba self-propelled vacuum cleaner or a remote-controlled toy are "motor vehicles" under the statute.

Sympathetic justices looked to the legislative history and saw that the law in question, the "Elizabeth Nowack-Washington Auto Theft Prevention Act" was designed to prevent automobile theft, not the theft of a comparatively less expensive lawnmower. They decided to narrow the scope of the ruling as a result.

"Though the definition of 'motor vehicle' could be more expansive in other statutes, the only statute at issue here is the theft of a motor vehicle statute," Justice Owens concluded. "Because of this, we hold that a riding lawn mower is not a 'motor vehicle' under RCW 9A.56.065."

Less sympathetic was Justice Steven C. Gonzalez, who disagreed with his colleagues, insisting that under the plain language of the statute, a lawnmower should be treated as a motor vehicle. He added that it is the job of the prosecutor to decide whether the charge is appropriate or not.

A copy of the ruling is available in a 1.3mb PDF file at the source link below.