Tires not rated for severe snow use may skid under icy conditions..

Mud and Snow icons on tire sidewall (courtesy Sullivan Tires)

Drivers seeking to comply with the increased enforcement of Colorado’s Code 15 traction law in the high country might be surprised to find that not all all-season tires comply with that law, said Amy Ford, spokeswoman for the Colorado Department of Transportation. She was quoted by Matt Kroschel reporting for CBS4 Denver. The new enforcement of Code 15 is for passenger vehicles traveling on Interstate 70 in wintry weather. That law, which previously was not enforced for passenger vehicles, requires cars to have snow tires or 4-wheel drive.

All-Weather Tires Versus Snow Tires

Even if a car’s tires have sufficient tread (1/8-inch minimum), drivers on I-70 in icy and snowy conditions can be fined $650 if their tires are not snow tires. Sergio Alvarez, manager of Big O Tires, a tire store near my location, said, “We are getting a lot of questions, folks not understanding what the traction laws are.”

Alvarez said it’s important for drivers to look at the sidewalls of their tires for a snowflake and mountain icon, to be compliant with Code 15. Driving with the wrong tires can cause loss of traction and skidding, possibly leading to a car accident.

All-season tires that are not compliant with the Code 15 law — and are merely all-season tires — have “M/S” imprinted on the sidewall, but no mountain or snowflake, said Sam Cole, CDOT communications manager. He explained that tires with the snowflake or mountain icon on their sidewalls are the ones that are “full-on snow tires” and thus compliant with Code 15.

Where’s the Spare?

In another safety-related tire topic in the news, Eric Tingwall wrote for Car and Driver that 36% of 2015 year vehicles are sold without a spare tire as standard equipment, according to AAA. Colorado AAA wrote in a recent press release that one of the items that drivers most often overlook is their spare tire, noting:

When inspecting tires, it’s important also to make sure the spare is in good condition and ready for use in case it’s needed.

But as Tingwall writes, even worse that having a flat tire is finding that you don’t have a spare.

He writes that automakers are desperate to reduce vehicle weight, in light of fuel economy standards for 2025 rising to 54.5 miles per gallon. And a spare tire is “arguably the lowest hanging fruit.” Automakers can reduce a car’s weight by as much as 30 pounds by simply eliminating a spare tire and replacing it with a 4-pound inflator kit. “[A]nd the donut can be removed without the extensive engineering or major investment other weight-saving technologies require.”

AAA found 136 2015 models that do not feature a spare tire as standard equipment, including at least one car per major automaker. That list is especially dense with sports cars, coupes, and hybrids, in which space comes at a premium. The list also includes many German luxury cars and crossovers, which often use run-flat tires.

Don’t Know Until It’s Too Late

In addition to the 2015 models, there have been more than 29 million new cars sold in the United States in the last 10 years that did not come with spare tires. He reports that all too often, drivers do not know about the lack of a spare tire until they are “stranded on the side of the road.” And even though most carmakers include an inflator kit when they are omitting a spare tire, such kits are only effective in certain situations: “on clean punctures through the center of the tread, such as picking up a nail, and the object must still be embedded in the tire to act as a plug.” An inflator can not be used when there has been a blowout, a curb strike, or when a pothole has caused the damage.

There is some good news, however: Tire technology has improved so that flat tires are becoming less common. Tingwall wrote that tire-maker Michelin estimates a driver averages more than 70,000 miles between flat tires.

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