Oregon's Chain Signs Have Four Levels, Not One
Date Published
Oregon runs a graduated system. The sign tells you which of four levels is in force, and a driver who reads every posting as chains now will chain up more often than the rule requires.
Who decides
Under OAR 734-017-0015, an Oregon Department of Transportation District Manager, or a person authorised by one, decides when conditions require a level and authorises the posting of the appropriate signs. Nothing is triggered by date.
The four levels
The first level requires that chains or traction tires be carried but not used. The equipment must be aboard; nothing has to be fitted.
The second requires chains on vehicles with a rated gross vehicle weight of 10,000 lb or less that are towing, and on single drive axle vehicles over 10,000 lb GVW.
The third requires chains on vehicles towing, or with a rated gross vehicle weight over 10,000 lb.
The fourth requires chains or traction tires on all vehicles except those exempt under ORS 815.145 and the division 17 rules.
The distinction between the second and third levels is the one that matters most to a heavy vehicle, because it is the point at which a tractor without a trailer stops being able to rely on traction tires.
Where the chains go
OAR 734-017-0010 sets placement by class. A solo commercial vehicle of 26,001 lb GVWR or more with a single drive axle chains one tire on each side of the drive axle.
Medium duty vehicles, between 10,001 and 26,000 lb, are handled separately: a single-drive-axle vehicle chains one tire on each side of the drive axle, and a tandem-drive-axle vehicle chains either two tires on each side of the primary drive axle, or one tire on each side of each drive axle if both are powered by the drive line.
Carrying enough
OAR 734-017-0012 closes the obvious gap. When chains or traction tires are required to be carried and the appropriate signs are posted, chains or traction tires of sufficient size and number to comply with the division 17 rules must be in or on the vehicle. Carrying one set for a vehicle that needs two does not satisfy the first level.
Why a graduated system
Chaining a heavy vehicle takes time and blocks a shoulder. A system that can ask for equipment to be carried, then for some classes to fit, then for all, lets the department escalate with the weather instead of choosing between doing nothing and stopping everyone.