Getting your car ready for a Colorado winter

From September 1 to May 31 the Traction Law is in force on I-70 between Morrison and Dotsero, and CDOT can activate it on any state highway: tires with 3/16 inch of tread marked "all weather", M+S or with the snowflake, or chains or an alternative traction device from CDOT's list. The fine is $100 plus a $32 surcharge, and $500 plus $156 if your non-compliance closes a lane (§ 42-4-1701(4)(a)(I)(F)). What to check before the first snow.

In Colorado the car's enemy is not a one-day storm: it is four months of cold, snow and road salt. Cold kills batteries, salt eats the frame and ice turns a curve into a crash. Here is what costs little in October and a lot in January.

Before the first cold (October)

• Battery tested. At 0 °F a battery delivers half its power. If it is over 3 years old, replace it before, not after.
• Winter or all-season tires with real tread (more than 4/32"). Summer tires harden in the cold and don't grip. Where snow is serious, winter tires are not a luxury.
• Coolant at the right level and mix (50/50). Washer fluid rated to −30 °C, not the summer kind, which freezes in the reservoir.
• New wiper blades, lights checked, defroster working.
• Winter kit in the trunk: scraper, brush, small shovel, blanket, gloves, sand or traction mat, jumper cables, flashlight, charger, snacks and water.
• Tank always above half: it prevents condensation and gives you heat if you get stuck.

When it snows

• Clear all of the car before leaving: roof included. Roof snow slides onto your windshield when you brake, or onto the car behind.
• Double your following distance. On ice, triple it. Brake gently and early; in a skid, look and steer where you want to go.
• Bridges and overpasses freeze before the road does.
• If you get stuck: stay in the car, exhaust pipe clear of snow, engine 10 minutes per hour, window cracked. Carbon monoxide gives no warning.

Salt: the damage you don't see

Road salt and brine corrode brake lines, fuel lines, suspension and the underbody. A car that spent winters here without underbody washes can have a compromised frame by year 8 or 10.

• Undercarriage wash every two weeks in winter and a thorough one in spring.
• When buying used in Colorado: look underneath with a flashlight. Surface rust is normal; flaking rust or holes in the frame rails and jack points are not.
• Ask where it spent its winters. A "southern" car carries extra value here for that reason.