The bill modifies the definition of "nonhighway vehicle" within the context of Washington's RCW 46.09, which pertains to nonhighway and off-road vehicle activities. Key changes include the specification that a "wheeled all-terrain vehicle" must now be 55 inches or less in width and weigh less than 1,500 pounds, while utility-type vehicles must have a maximum width of 74 inches and a maximum weight of 3,500 pounds. Additionally, the bill clarifies that nonhighway vehicles do not include certain watercraft, snowmobiles, military vehicles, or vehicles eligible for fuel tax exemptions while such exemptions are claimed.

The bill also updates the definition of "nonhighway road" to include roads not constructed or maintained with motor vehicle fund appropriations in the last 25 years and the last four years, respectively. Other definitions related to recreational users and facilities are retained or slightly modified to ensure clarity and consistency in the law. Overall, the bill aims to enhance the regulation and understanding of nonhighway vehicle use and related recreational activities in Washington State.