Illegal to Mow Grass Into the Road: Depositing grass clippings on the road illegal per “Wisconsin Statute § 346.94(5). The statute addresses “placing injurious substance on highway” and states: “No person shall place or cause to be placed upon a highway any foreign substance which is or may be injurious to or damaging to any vehicle or part thereof, or which is or may be injurious to or damaging to any person.”* While the statute doesn’t explicitly say “grass clippings,” the language is intentionally broad. Courts and law enforcement agencies widely interpret grass clippings as a “foreign substance” that is “injurious to… any person.” The slick surface they create poses a direct threat of injury, clearly falling under the statute’s purview. A violation of this statute is a non-criminal offense, but it does come with a penalty. The forfeiture (the Wisconsin term for a fine for this type of violation) can range from 50to50to200, plus court costs. While not a massive sum, it’s an easily avoidable expense.” Source: Is It Illegal to Mow Grass Into the Road in Wisconsin? Here’s What the Law Says