A longtime Minneapolis federal judge suggested in a ruling this week that the Legislature should consider defining snowmobiles as motor vehicles to allow accident victims to collect damages from uninsured riders.

Such a change would have a potentially broad impact in Minnesota, which has more than 250,000 registered snowmobiles — more than any other state.

The question of whether a snowmobile should be considered a motor vehicle for insurance purposes was addressed by the state Supreme Court as far back as 1974. It ruled then that they aren’t motor vehicles because they aren’t designed for use on public highways.

Earlier this week, U.S. District Court Judge John Tunheim reinforced that long-standing definition in a case involving a 2011 injury crash in St. Louis County involving a semitrailer truck driver and a teen snowmobiler. Tunheim ruled against the truck driver, saying his insurance company did not have to provide additional “underinsured auto” coverage because the state’s No-Fault Act, which helps provide economic relief for uncompensated auto accident victims, excludes coverage for snowmobiles.

The case, Tunheim wrote, illustrates that the Legislature’s choice to exclude snowmobiles can have major financial consequences when snowmobiles are involved in crashes on public roads — something that happened 28 times in Minnesota in 2013 alone. South Dakota now includes snowmobiles for similar coverage.

“Unless and until snowmobiles are covered by the No-Fault Act, Minnesota courts have little relief to offer victims of public roadway collisions with uninsured snowmobiles, even where those victims would likely be entitled to insurance benefits if the snowmobile were, instead, another motor vehicle,” the judge wrote.

Tunheim’s case involved United Financial Casualty Co. and Bradley Nelson, who was driving a semi about 5 p.m. on Jan. 29, 2011, near a county road called the Vermilion Trail in Colvin Township. Joseph Tynjala, then 17, tried to cross the road from a ditch on his snowmobile.

Tynjala failed to yield the right-of-way to Nelson, who was going about 50 miles per hour and tried to avoid him. They hit head on, and Nelson ran over Tynjala’s snowmobile, lodging it under the trailer. Nelson was injured in the crash. Police determined that Tynjala, who was slightly injured, was at fault.

The snowmobile was registered to family member Carol Tynjala, who had it covered under her home but not auto insurance. Nelson received about $100,000 from Tynjala’s home insurance policy. Because the snowmobile wasn’t insured under an auto insurance policy, Nelson also sought underinsured motorist coverage from his own policy with United Financial.

Nelson’s policy defined “auto” as a land motor vehicle or trailer designed for travel on public roads. The policy excludes mobile equipment mainly used off public roads, such as bulldozers, farm implements, forklifts or vehicles that travel on crawler treads.

United Financial asked Tunheim to order a summary judgment against Nelson because a snowmobile didn’t qualify as an auto under the insurance policy. The insurance company pointed out that the safety handbook for Tynjala’s specific snowmobile cautions riders to avoid road travel because the snowmobile isn’t designed to operate or turn on paving.

Nelson’s attorney argued that the language in his policy states that equipment designed mainly for use off public roads might on occasion be used on them. He referred to a 1974 case involving the crash of two snowmobiles that would allow Nelson to escape automatic exclusion under the “underinsured auto” provision.

Tunheim knocked down that argument, saying Tynjala was barely on the road when he hit Nelson’s vehicle. He also said a snowmobile isn’t an auto because it travels on crawler treads.

Although the No-Fault Act excludes snowmobile coverage because they are designed for off-road travel, Tunheim also wrote that it’s undeniable that snowmobiles frequently are driven on snow- and ice-covered public roads. Many Minnesota communities have officially recognized that fact by allowing snowmobiles on local public roads.

Tunheim wrote that South Dakota’s legislature has addressed insurance coverage for snowmobiles under its mandatory motor vehicle insurance rule, defining motor vehicle as “every vehicle which is self-propelled.”

Attorney Bill Davidson of Lind, Jensen, Sullivan & Peterson, who represented United Financial, said he was pleased with the judge’s decision regarding the language of the insurance contract. Because the decision could be appealed, he declined further comment.

Kelly Klun, who represented Nelson, didn’t return a telephone call.