Colorado traction law starts to pay minor I-70 dividends |

Colorado traction law starts to pay minor I-70 dividends

New law is complicated, but people are starting to ask what kinds of tires they need

Devices such as AutoSocks are required in passenger passenger vehicles that don't have "winter-capable" tires.
What’s the law?
  • All tires must have at least 3/16 inch of tread.
  • Two-wheel-drive passenger vehicles must have either “winter-capable” tires or traction devices at all times between September and May.
  • Four-wheel-drive passenger vehicles must have tires with at least 3/16 inch of tread.
  • The fine is $650 if you cause a highway closure and don’t have appropriate tires.

State officials for years have tried to simplify Colorado’s winter traction laws. The Colorado legislature in 2019 passed such a law after years of trying.

It’s still early, but the new law seems to be having some success.

“We are seeing more awareness of the topic — we’re seeing questions all the time,” said Andrew Hogle, a public information officer for the Colorado Department of Transportation. But, Hogle added, there’s a “ways to go” regarding public understanding of the law.

With that in mind, here’s a quick rundown of the basics.

The law is aimed mostly at Interstate 70 between Dotsero and Morrison.

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That’s the simple part. The law gets most complicated regarding two-wheel-drive vehicles.

Those vehicles need to have “winter-capable” tires. Motorists need to look at their tires’ sidewall markings to determine winter capability. Hogle said those tires have one of two markings, either a snowflake or the designation “M+S,” meaning “mud and snow.” Those tires must have a minimum tread depth of 3/16 inch.

Put a sock on it

Vehicles without winter-capable tires must carry alternate traction devices. That means either chains or a device called an AutoSock. Name brand AutoSocks can be $100 per pair or more. Still, that’s less expensive than new tires. It can also be less expensive than a ticket for not having adequate tires or traction devices. That ticket is $130. Drivers can be cited for that offense if they’re pulled over for another reason, in any conditions, at any time between September and May. If an officer checks, and you don’t have the right tires or traction devices, you may get a ticket.

If you’re running on inadequate tires and cause a lane closure during a snowstorm, you will get much more expensive ticket — $650.

Hogle said the good news is that M+S tires seem to be becoming something of an “industry standard,” particularly as original equipment on new cars.

That means more rental cars come with M+S tires. In fact, Hogle said, most rental cars at Denver International Airport are now equipped with M+S tires.

But, he added, it’s up to customers to determine what kind of tires a vehicle has.

“Ultimately drivers are responsible,” Hogle said. “We want people to know as much as possible.”

The law is more simple for four-wheel or all-wheel-drive vehicles. Hogle said the law mandates only a tread depth of 3/16 inch.

Hogle said early data is encouraging. Every winter is different, particularly regarding when storms hit. But, Hogle said, the 2019-2020 season so far is similar to the 2017-2018 season. There seem to be fewer lane-closing incidents this winter just like two seasons ago, he said.

Winter tires are best

Still, tires with snowflakes are most likely to work better in winter conditions.

“We encourage everyone to have winter tires,” Hogle said. “But it’s a cost concern — not everyone can afford a second set of tires.”

First responders from the town of Vail spend a lot of time on the west side of Vail Pass. Vail Police Chief Dwight Henninger said he believes the traction law in its first year may have resulted in some “minor improvements — maybe more than I’ve seen.”

In Henninger’s view, there’s a still a lot more to be done regarding public education about the law.

While acknowledging that the law’s details are “really complicated,” Henninger said there needs to be a better communications effort to the public. But, he said, the Colorado State Patrol, Department of Transportation and other state and local agencies are working on education efforts that could be in place when the next winter season begins.

Hogle noted there are already a number of information resources for motorists, including, and Motorists can also dial 511 for statewide road information.

Hogle acknowledged the complexity of the current regulations, adding that the legislature may tweak the existing law in this session.

Ultimately, though, the regulations are too much to put on a bumper sticker or variable message sign on an interstate, he said.

But Henninger said, efforts to keep I-70 traffic flowing have improved since a massive storm in early 2014 resulted in some travelers facing a 10-hour drive from Edwards to Denver.

No matter what the regulations, though, Henninger said people should have an emergency kit in their vehicles, just in case. Henninger’s own kit includes clothes, food and an emergency blanket, an extra pair of boots and a shovel.

And, he added, while keeping the highway clear is better than it was, another giant storm, or a serious avalanche, could result in another traffic disaster.

Vail Daily Business Editor Scott Miller can be reached at of 970-748-2930.

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