Now, most of the readers of this blog that I know of are sensible, capable individuals who don't need advice on routine matters such as driving in snow. But perhaps the little bit of advice contained herein will somehow find its way out to that chorus of "other people" who fill our days with the sonorous tones of engines gunning and tires skidding.

(Warning: For those who aren't in the mood for a long exploration of minutia, you might want to log off, go get some coffee, and get on with your day.)

Since our big snowfall a couple days ago, I've seen or heard literally dozens of people who seem to revert to a different state when driving in snow, something akin to Frankenstein's monster, the Hulk, an angry Homer Simpson, or a frustrated child. Seemingly never having really paid much attention to the dynamics of how their car moves and interacts with its environment, they not only rely completely on the controls of their car, but use them like a video-game controller--as a series of buttons or on/off switches with no subtlety.

The prime example of this, of course, is the type who guns their engine, floors it, when they start getting stuck in snow. Like the instinctive dumbing-down that happens when you're playing a video game and keep hitting the "fire" button in a desperate attempt to get out of the bind you're in, these people seem to view their gas pedal as a "go" button. Car not go? Hit button. Hit button again. Hit button harder. Harder! Hulk smash!

I wonder how many of these people notice that when they're cruising along and jam on the gas, the result is actually a braking effect? That the action is actually digging their car in?

The truth is, cars are big and heavy, and once you get them rolling, they tend to keep rolling unless stopped by a barrier. And a snowy road isn't much of a barrier to something that big and heavy. The tires, under the weight of the car, will tend to roll pretty easily at the natural speed of the car's body. It's when we change the forces operating on the tires and the body that the overall equation changes and crazy things start happening.

Step on the brakes, and you're adding resistance to the natural rolling of the tires against the packed-snow road. Do this too hard or too fast, and you set up a competition between the energy of the moving weight of the car and the ability of the tires to grip the road--and the weight of the car will usually win. Thus, the wheels lock and the car slides--the weight of the car has won the battle, and that momentum-energy is flowing freely in two dimensions, without the controlling factor of the tires' directed friction.

Similarly, step on the gas, and you're also setting two energies against the other--in this case, it's the opposite scenario, as you're trying to overcome the weight of the car with the force of the wheels' rotation and their traction with the ground. This is, of course, how cars move--the force channeled into the rotating of the wheels overcomes the downward weight of the car, making it move. But in this case, there's an unsure connection between the tires and the road, and so the energy doesn't translate into the normal traction. Without that traction, the force of the wheels turning overwhelms the limited resistance available and "breaks free", and the tires spin, unimpeded by the road surface.

The connection between these two conditions is an imbalance of forces--the overwhelming of one force by another, throwing things out of whack. The same things can happen on everyday dry roads under clear and warm conditions. People "peeling out" on dry pavement overwhelm their traction on the road with an application of immense wheel-spinning force, and the result is tires that spin out of proportion with the car's movement, resulting in the tires grinding against the road like a belt sander, tearing them up and leaving those black marks. The same thing happens when you make a brake-locking emergency stop on dry pavement and your car skids--the traction of your tires falls to the great energy of the car's moving weight, and you skid and leave scraped-off tire in your wake.

So in a sense, we're really always driving under the same physical conditions. It's just that normally, there's such a large safety margin that we're never aware of the boundaries where we can lose control. The speeds we normally drive at, the friction of the tires on the road, the materials in the roads themselves, and the amount of power we have available in our engines and brakes are all in pretty good balance--they're designed to work together to produce predictable, easily manageable results. Stopping and starting are routine affairs as a result.

This can, however, lull us into complacency, into thinking of the controls on the car as simple "stop" and "go" buttons. When, in fact, they're more like "application of force" dials, or flasks of different chemicals that can combine into either a stable or unstable compound when mixed in different measures. All the elements are part of a system that is designed to work flawlessly within certain typical boundaries, but which--through a change in the external conditions, or a change in the forces we have control over--can be upset.

And if that happens, suddenly it's you and a few thousand pounds of metal and you're floating freely in a mix of very powerful forces--just like that, it's Physics 101, and if you had as much trouble as I did with physics in high school, that can be daunting.

In those moments, the best success I've had is with a combination of Douglas Adams and the Buddha--don't panic, accept your situation, and let go of what you can't control. It's amazing how smoothly things can go, for example, if you just coast through the slippery spot. It's scary to not be able to stop or speed up, to just let go of those controls, hold the steering wheel, and ride it out, but it's also the best way to balance the forces at work and not either get stuck in a rut or slide out of control. Then, in that moderated, controlled state, apply those forces in a gentle and patient way, and most of the time the result is better than any application of overwhelming force can be.

Well, somehow I've managed to go from humor to amateur-hour physics to philosophy in a post about driving in snow, so I think I'd better get out of my own head for a bit and stop now. For more tips on driving in snow and ice, see the following:

• Tips from State Farm
• Sensible advice from the Brits (of course)
• Wisdom from the all-knowing gurus in Pueblo, Colorado
• NHTSA tips

(Note: as I've been writing this, I've heard at least four drivers outside my window struggling and/or getting stuck by gunning their engines in the snow.)

Labels: Life