The ultimate guide to traction tires, chains, and studs I PEMCO

Heading over a mountain pass this holiday season (or even this week)? Winter in the Pacific Northwest can turn mountain passes into blizzard zones, with low visibility and roads as slick as ice rinks. Whether you’re heading over the Cascades or just making a brief holiday trip, safe winter driving starts with preparation. 

The best way to avoid winter driving emergencies is to plan ahead, know the rules, and carry the right gear. Having the appropriate tires is required over passes, but it’s also important for preventative action that can reduce risk when navigating the infamous steep and twisting terrain across the region.  

What are “approved traction tires”? 

Both Washington and Oregon require “approved traction tires” when conditions call for them, especially when traveling across mountain passes during the winter. Tread depth, pattern, and other traction-enhancing characteristics combine to qualify as a traction tire. Learn more about what qualities each type provides:  

• M+S tires: Marked for mud and snow. 
• Mountain/snowflake symbol tires: True winter tires designed for cold weather grip. 
• All-season tires: Acceptable, but less effective than winter tires in icy conditions. 
• Studded tires: Legal Nov. 1–March 31 in Washington and Oregon, but they damage roads and don’t replace chains. 
• Chains: Adding chains makes any tire an approved traction tire. 

Heavy-duty pickups and vans over 10,000 pounds must use chains when required, not just traction tires according to the Washington State Department of Transportation. 

Are all-season tires the same as winter tires? 

No. Winter tires use softer rubber and aggressive tread for grip at low temperatures. They wear faster, so we recommend using them only during the winter season (roughly Thanksgiving through Easter). 

All-season tires may carry the M+S marking but don’t perform as well on ice.  

Prevention tip: If you regularly cross passes, invest in winter tires for safety. 

Do you need winter tires? 

When considering your winter tire needs, consider where you will be driving. But most importantly, don’t wait until you’re stuck, equip your car before the storm. 

• Metro areas west of the Cascades: All-seasons may suffice if you avoid icy conditions. 
• Rural, rugged, or hilly areas: Winter tires are strongly recommended. 
• Crossing passes: Winter tires or chains are essential. 

What about studded tires? 

In general, studdless winter tires are better for all-around performance and less road damage.  

• Best for clear ice or steep, icy driveways. 
• Legal only Nov. 1–March 31 in WA and OR. 
• Banned in some states—check laws if traveling cross-country at truckclaws.com. 

Does four-wheel drive help? 

• 4WD improves traction when starting out. In other words, it helps you go but not stop. Drive cautiously. 
• It does not improve braking or steering on ice. 
• Overconfidence risk: Drivers often assume 4WD makes them invincible. 

Does “chains required” apply to all cars? 

Yes, when signs say, “chains are required on all vehicles,” even AWD and 4WD must chain up. 

• Studded tires do not count as chains. 
• Carry chains for at least one set of drive wheels. 
• Practice installing chains before your trip. Don’t wait until you’re on the side of the road in a snowstorm—know how to chain up before you go. 

Key prevention reminders 

• Carry chains in your vehicle at all times during winter. 
• Check pass conditions before you travel. 
• Slow down — speed limits assume dry pavement. 
• Leave extra space for braking. 
• Pack an emergency kit: blankets, food, water, flashlight, and phone charger. 

Winter driving in the PNW is unpredictable. And remember, traction tires, chains, and proper preparation aren’t just legal requirements—they’re lifesavers. Tackling winter travel (especially across the passes) with prevention in mind means fewer roadside emergencies and safer holiday travels. 
 

NOTE: While we’re experts in loss prevention and home/auto safety, we don’t consider ourselves experts in traffic laws or their enforcement. Information shared here is for educational purposes only and is not legal advice. If you have legal concerns, we urge you to contact a law enforcement source or attorney in your community.