North Dakota Studded Tire Season: October 15 to April 15, One-Sixteenth Inch Projection Limit

The controlling provision is section 39-21-40 of the North Dakota Century Code, titled "Restrictions as to tire equipment", inside chapter 39-21 on equipment of vehicles. Subsection 3 states the general rule first: no tire on a vehicle moved on a highway may carry on its periphery any block, stud, flange, cleat or spike, or any other protuberance of a material other than rubber, that projects beyond the tread of the traction surface. Studded snow tires are then carved back out of that prohibition by a sentence that imposes two conditions at once, a calendar window and a dimension. The window runs from October fifteenth to April fifteenth. The dimension is one-sixteenth of an inch, which the statute also prints in metric as 1.59 millimeters, measured as projection beyond the tread of the traction surface. A stud that sits flush or below is not reached at all; a stud that stands proud of the tread by more than a sixteenth of an inch is unlawful even in January.

The schoolbus exception is written into the same sentence and is unusual in that it removes the calendar rather than the dimension. A schoolbus may use studded pneumatic tires at any time during the year, and the one-sixteenth inch projection limit still applies to it. North Dakota grants no equivalent year-round allowance to emergency vehicles, mail carriers or rural school staff, so a district activity van that is not a schoolbus stays inside the October to April window.

Two other allowances sit in the same subsection and are commonly confused with the studded-tire rule. Farm machinery may run tires with protuberances so long as those protuberances will not injure the highway, and that allowance carries no season. Tire chains of reasonable proportions are permitted outright, with no calendar limit and no projection figure, which matters on the Missouri Plateau and in the Turtle Mountains where a spring storm can arrive after the April fifteenth cutoff has closed the studded-tire window. Chains remain lawful on that day; studs do not.

Subsections 1 and 2 of the same section handle the older problem of hard tires. Every solid rubber tire must carry at least one inch of rubber across its entire traction surface above the edge of the flange, and no motor vehicle, trailer or semitrailer may be operated or moved on a highway with any metal tire in contact with the roadway. Those rules run all year and have no winter exception, so a bare steel wheel or a worn solid tire is unlawful in February exactly as it is in July.

Scope limits come from section 39-21-46. Subsection 5 says the chapter's equipment provisions do not reach implements of husbandry, road machinery, road rollers or farm tractors except where a section is specifically made applicable, which is the structural reason the farm machinery allowance in 39-21-40(3) reads the way it does. Subsection 7 excludes vehicles moved solely by human power. Subsection 6 excludes motorcycles and motor-driven cycles from the chapter's provisions with respect to equipment required on vehicles, which is a requirement clause rather than a restriction clause, so a rider should not treat the tire restriction in 39-21-40(3) as switched off for a motorcycle.

North Dakota runs no periodic safety inspection for passenger vehicles, so nothing measures stud projection on a schedule. The rule is enforced at the roadside by the Highway Patrol and by city and county officers, which in practice means the calendar matters more than the dimension: an officer can read a date without a gauge.

Section 39-21-46(1) makes it unlawful to drive or move a vehicle that the driver knows is equipped in violation of chapter 39-21, and to do any act the chapter forbids where no other fee or penalty is set. A studded-tire violation is therefore charged under 39-21-40 by way of 39-21-46. 1-02, disposed of by paying the statutory fee to the designated official or by forfeiting bond. 1-06(2) sets the fee for a moving violation at twenty dollars unless a specific higher figure is listed, which it is not for section 39-21-40.

Bond posted by mail must be submitted within fourteen days of the citation, and if no hearing is requested in that time the bond is forfeited and the violation admitted. 1-10(3) assigns two points for knowingly driving with defective, nonexistent or unlawful equipment in violation of section 39-21-46. Twelve accumulated points brings a seven-day licence suspension, and each point above eleven adds another seven days. A driver who wants a hearing may appear before the designated official, make a statement in explanation of the driver's action, and ask that the fee or bond be waived, reduced or suspended. 1-32-01(7).