A Feb. 26, 2015, story from Canada reports that “Modern plastic vehicle parts (are) cracking under temperatures.” The story states that the flexible plastics used in the manufacture of cars today “easily ‘shatters’ when temperatures dip below -20 C.”

It’s Canada. It’s -20 C. That’s darn cold. That’s an Arctic temperature. We don’t have to worry, right?

Guess again. A conversion chart shows that -20 Celsius is actually only -4 Fahrenheit. Here in McHenry, we have temperatures that fall below -4 degrees every winter. You can plan on it. You can set your watch by it.

Newer cars have traded traditionally metal parts for plastic parts, what the story referred to as “thermoplastic olefin.” The advantage, other than cost savings in producing the parts, is that the plastic parts weigh less. That means that the cars, trucks and SUVs weigh less.

When a car, truck or SUV weighs less, the engine doesn’t have to work as hard to move the vehicle. Think about it. If you were going to pull an empty wagon up a hill, or the same wagon loaded with 50 pounds of weight, you would have to work harder to pull the latter wagon.

The same principle holds true for your car, truck or SUV, whether you’re driving up a hill in McHenry or anywhere else (unless the road on the McHenry hill is slick with ice).

When your car, truck or SUV engine has to work harder, it burns more fuel. This means that a heavier car, truck or SUV will have lower gas mileage than the same vehicle made with heavier metal instead of plastic.

These are the reasons that the plastic is a significant advancement in the manufacture of vehicles today. The problem, as the Canadian article points out, is that the plastic may not handle the extreme cold temperatures well.

It isn’t necessarily that the plastic simply breaks. Rather, it’s a question of the plastic becoming brittle. When the plastic is brittle like that, the slightest bump against the curb on Green Street in McHenry can fracture the plastic.

This also means there isn’t much you can do about it, except to drive carefully so you don’t bump when brittle.