Northern Arizona is at a much higher elevation and when winter comes around the dry hot region becomes wet and slick and frozen. This produces dangerous driving conditions and catches some motorists unprepared.
Perhaps nobody knows this better than folks who work for the Arizona Department of Transportation. This is evident in the fact that ADOT has already released their winter advisory warnings to motorists who might be traveling in the northern portions of the state. Among their suggestions is always keeping at least 3/4 of a tank of fuel in the car. This is both so drivers don’t have to worry about running out of gas if they get caught in traffic and so their car has a little added weight to improve traction.
For cars with rear-wheel drive adding a little extra weight in the rear of the vehicle can make all the difference on slick roads. That extra weight on the axle improves traction, no doubt about it. In some northern states, like Michigan and Wisconsin, drivers will put sandbags or even chopped firewood in their trunk as a way of increasing the weight in the rear of their car. Conventional wisdom, and experience, tells them that the extra weight will help them from getting stuck or slipping and sliding off the road when the weather turns bad.
We suppose you could accomplish the same thing by putting your friends in the backseat of your car every time you go driving somewhere, but then you’d have to worry about stopping for restroom breaks, arguing over the radio stations or aving to put up with inane conversation. instead, use an inanimate object and make your vehicle safer and quieter.