A Summit County motorist’s guide to winter driving and traction laws

Use a quarter to check your tires tred. If George Washington's head pokes below the rubber, you are good to drive when the Traction Law is in effect.
Getty Images / iStockphoto | iStockphoto

Winter weather has arrived, which can mean extremely dangerous road conditions for motorists driving through the mountains. If you’ve driven up the I-70 corridor during a storm lately, you’ve likely noticed signs about traction and chain laws going into effect.

But what exactly do they mean?

Traction laws are put in place when conditions on the roadway become dangerous due to winter weather like snow, ice and wind, and can be issued by Colorado State Patrol, the Colorado Department of Transportation and even snowplow drivers who notice hazardous roads on their routes. The goal is not only to protect drivers without the proper vehicles or tires, but also to avoid any major pileups or road closures due to unprepared drivers.

“Clearly I-70 is a main artery in Colorado for freight trucks, passenger vehicles and people coming up to ski,” said Tracy Trulove, spokeswoman for CDOT. “We find that when people are prepared and drive for the conditions, slowing down to get where they’re going, the conditions can be navigated. It’s the people in a hurry, not prepared to drive in these conditions or not used to driving in a Colorado winter that end up in a ditch or causing a chain reaction on the highway.”

There are two different types of laws that can come into place during extreme weather conditions: the traction law and the passenger vehicle chain law. The traction law, which is typically enacted with commercial chain laws, requires tires on all cars to have at least 1/8 of an inch of tread. Additionally, all non-four-wheel drive vehicles must be fitted with either snow tires or tires with a mud and snow (M+S) designation.

CDOT recommends using the “quarter test” to determine the size of the treads on your tires. Simply insert a quarter into the tread with George Washington’s head going in first. If the top of Washington’s head is covered by the tread, the tires are acceptable. The test should be done around different areas of the tire, and if the top of the head is visible at any point, new tires are required.

If weather conditions are especially treacherous, the passenger vehicle chain law may go into effect, requiring every vehicle on the roadway to have chains or an alternative traction device like AutoSocks. Trulove noted that passenger chain laws are rarely instituted, and typically occur before a road is closed entirely.

“We’ll use it if we’re not able to keep up with the snow, and we’re not able to keep the highway safe with just the traction law,” explained Trulove. “Most times we’re pretty close to closing roads right afterwards if we enact the passenger chain law.”

Despite signs and warnings on social media during storms, traction laws are often ignored, either because motorists are ignorant of their meaning or because they’re overly confident of their winter driving abilities.

“It’s a dynamic environment,” said Colin Remillard, public information officer with the Colorado State Patrol. “People have to understand that this is a high-alpine environment, and the weather can change rapidly. If you’re not prepared you’re not going to be able to safely travel up here. You become part of the problem instead of part of the solution. I would say that with a large storm, there’s people ignoring the laws every time. Whether it’s chain laws for trucks, or tourists in rental cars, there’s at least a few in every major storm.”

Trulove said that the potential punishments for failing to follow traction laws range from $130 to more than $650 in fines depending on the severity of the storm, and why you got pulled over. In other words, if you simply get pulled over with inadequate tires you’ll likely receive a fine on the lower end. But if you cause a pileup or chain reaction that shuts down the highway, your fine will be much heftier.

Aside from fines, failing to adhere to traction laws can lead to major traffic delays and serious headaches for motorists.

“If you have a bunch of cars that can’t get up the hill it plugs everything up,” said Remillard. “When you’re stuck on the road there are not a whole lot of places to go. When people ignore or are ignorant of those rules it can jam up this county pretty good.”

Officials with CDOT recommend that drivers in the area invest in a set of snow tires, and say that all-season tires typically aren’t sufficient in the mountains. At 60 miles per hour on snowy pavement, snow tires need about 310 feet to stop, while all-season tires require more than 660 feet to stop.

Additionally, CDOT recommends leaving extra room between your vehicle and others on the road when it’s snowing, taking things slow and giving snow plows plenty of space to work. CDOT also has several resources to help travelers navigate tricky conditions more easily. gives updates on road conditions, closures and even gives realtime updates of where snow plows are operating.

CDOT also recommends keeping a winter driving vehicle kit in your car complete with blankets, water, a flashlight, a shovel and food. If you’re stuck inside your car in a serious storm, officials say not to leave your car, run the engine periodically and wait for help. But perhaps most importantly, officials warn that if you’re not experienced driving in the snow, trying your luck during a storm is a bad idea.

“People who haven’t outfitted their cars with the proper tires might want to rethink being up in the corridor,” said Trulove. “And if you don’t have experience driving in the Colorado winter, it’s probably not a good time to get experience.”

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