M+S or Winter tires required in western U.S.?
I did a search of DOT websites. It appears M+S or winter (mountain-snowflake marked) tires are not required in WA, ID, MT, UT, CA, NV, AZ unless conditions warrant authorities to require them i.e....
Forum Discussion
We prefer to run snow tires any time there may be chain controls. I don't like to run on bare pavement (sunny or well plowed areas) with chains, and I really don't like to install and remove chains on a single trip. I don't recall the last time I actually had to install chains in a chain control area; snow tires + 4WD are almost always sufficient for me.
To clarify California chain control restrictions (they were stated somewhat incompletely above):
All vehicles (including 4WD) are required to carry chains in chain control areas at all times.
R1: Chains required on drive axle of 2WD vehicles. No chains required for 4WD and no tire restrictions for 4WD (i.e. you could technically use all season tires).
R2: Chains required on drive axle for 2WD vehicles. 4WD vehicles must have snow tires (mountain + snowflake symbol); "Mud+Snow" tires are NOT acceptable.
R3: Chains required on all vehicles. CHP usually closes the road before implementing R3 restrictions.
To clarify California chain control restrictions (they were stated somewhat incompletely above):
All vehicles (including 4WD) are required to carry chains in chain control areas at all times.
R1: Chains required on drive axle of 2WD vehicles. No chains required for 4WD and no tire restrictions for 4WD (i.e. you could technically use all season tires).
R2: Chains required on drive axle for 2WD vehicles. 4WD vehicles must have snow tires (mountain + snowflake symbol); "Mud+Snow" tires are NOT acceptable.
R3: Chains required on all vehicles. CHP usually closes the road before implementing R3 restrictions.
