Oregon Studded Tire Window: Nov. 1 to April 1, and ODOT Can Move It

Read the two sections in order, because the drafting is unusual. ORS 815.160(1)(a) makes it the offence of unlawful use of metal objects on tires to drive or move on a highway any vehicle equipped with a tire carrying "any block, stud, cleat, bead, chain or other protuberance of metal or other inflexible material" that projects beyond the tread or traction surface. Subsection (1)(b) reaches the registered owner who causes or permits it, and provides that operation in violation is prima facie evidence that the owner permitted it. Only then does ORS 815.165 list twelve exemptions, and studded tires sit at exemption (7). So in Oregon the lawful winter tire is a carve-out from a prohibition, not a permitted accessory.

The window in the statute runs "between November 1 of any year and April 1 of the following year." ODOT states the season publicly as November 1 through March 31 and warns that driving on studs before November 1 or after March 31 carries a fine of nearly $200. The studs must project not less than four-hundredths (0.04) inch and not more than six-hundredths (0.06) inch beyond the tread surface, and must be made of material that wears at the same rate as the tread. The same sentence hands the Department of Transportation power to shorten or lengthen the permissible period "in any area of the state specifically designated by the department" when preservation of the highway surface or the safety of the traveling public so indicates. That is an area-specific power, not a statewide switch, so an extension granted for a mountain county does not travel to the Willamette Valley.

Retractable studded tires escape the calendar entirely. ORS 815.165(12) exempts vehicles equipped with retractable studded tires as defined in ORS 815.045, and ORS 815.045(1)(b)(E) defines them as tires with embedded studs that project beyond the tread surface only when the operator extends them to augment traction. ODOT adds that the studs must retract to at or below the wear bar of the tire and project not less than 0.04 inch when extended. There is also a supply-side rule most drivers never see: under ORS 815.167 a tire dealer may not sell a tire equipped with studs that are not lightweight studs, and may not sell a non-lightweight stud for installation in a tire. Lightweight is defined by weight, at 1.5 grams for stud size 14 or less, 2.3 grams for sizes 15 and 16, and 3.0 grams for size 17 or larger, and the stud must be one the tire manufacturer recommends for that type and size of tire. Retractable studs are exempted from that dealer restriction.

Oregon then bolts a separate chain-control regime onto the same chapter, and it is the part that actually stops traffic in the passes. ORS 815.140 creates the offence of failure to use vehicle traction tires or chains, and ORS 815.142 the offence of failure to carry them. Both bite only where a road authority has determined that conditions on a segment require them and has posted signs, under rules the Oregon Transportation Commission adopts through ORS 815.045. Subsection (5) of each section gives a defendant an affirmative defence: a court may not convict if it finds that highway conditions at the time of the citation did not require posting. ORS 815.145 exempts police vehicles under any conditions, fire vehicles responding to a fire, and ambulances responding to an emergency, and excuses a passenger vehicle or truck from chains if it weighs 6,500 pounds or less unloaded, is powered on both front and rear wheels, is carrying chains, wears traction tires on all wheels, is not towing, and is not being operated where it loses traction while stopping, cornering or moving.

ODOT operates that regime through signs and conditional closures. In typical conditions a vehicle rated 10,000 pounds gross vehicle weight or less and not towing may substitute traction tires for chains, and ODOT defines traction tires to include studded tires, retractable studded tires, and tires marked with the three-peaked mountain and snowflake emblem for severe snow service. In bad conditions ODOT may impose a conditional closure requiring chains on all vehicles regardless of tire type, a step it says is frequent on Interstate 5 through the Siskiyou Pass south of Ashland, where a typical order reads that chains are required on all vehicles excluding four-wheel drive vehicles unless towing. Chain placement by axle and vehicle class, down to which tire of a dual-wheel axle must be chained, sits in Oregon Administrative Rules chapter 734, division 17. Motorcycles are exempt from carrying chains or traction tires and may not travel when chains or traction tires are required.

188, and up to $1,000 for a corporation. ODOT describes the real-world cost as close to $200 once the surcharge is added. The exposure does not stop at the fine. 160 among the violations for which the owner and the driver are jointly and severally liable to the state, the county or the city for all damage done to the highway, street or bridge, with liability running to whichever government owns the road. 140 is also a Class C violation for ordinary drivers, but subsection (7) turns it into a specific fine violation with a presumptive fine of $880 where the vehicle was registered under ORS chapter 826, the chapter covering vehicles registered for interstate commercial operation. 142 is a Class C violation. 142(5) defence that conditions did not require posting.