Holiday stress comes in all shapes and sizes. You’re making a special dish for Christmas dinner, for example, and even though you’ve prepared it a thousand times before, this time the crust won’t hold together.

At dinner, the conversation deteriorates when your uncle Harry starts talking about his latest gout flare-up, and the topic lingers into dessert.

Then there’s the cross-country holiday drive. It can be relaxing if you don’t run into car problems – or a traffic jam. But on long holiday trips at least one jam-up is almost inevitable. I inched my way through two of them this year during a 2,000-mile round-trip from West Palm Beach to Baltimore.

Stop. Roll 5 feet. Stop. Get up to 10 mph, slam on your brakes. This is tough enough, but more stress comes from what you can’t see: the source of the problem, or how long it might go on.

There’s a theory that getting into a traffic jam actually may have some psychological benefits because it gets your mind off other, even more stressful things, like work. But what’s the good of trading one brand of stress for another?

Instead, I like the idea of viewing the traffic jam as a temporary community. You have neighbors you see again and again, sometimes behind you, or to the right or left.

After a second or third glance, you know a little about them. You know what state they’re from and sometimes what city. You know what kind of car they drive, and whether they are self-important enough to have a vanity plate. You know roughly what age group they fall into and whether they are a family unit.

You can speculate that the middle aged guy in the silver Mercedes convertible who’s talking non-stop on his cell is recently divorced, living in an urban bachelor pad just up the block from a Starbucks. You figure that the elderly couple driving the SUV and pulling a travel trailer with New York plates, heading south, are on their way to a Florida RV park until April.

You may spot a narcissist. He’s the guy going 50 mph in the far-right lane, the one marked “Exit Only” a half-mile ahead. And when he reaches the exit, at the very last second, he pops his turn signals on and squeezes back into traffic where he finds it most convenient.

You may see an outlaw. These are the ones who abandon the road completely and take to the shoulder, gambling that an emergency vehicle won’t be coming the other way, or will need to pass him from behind. And if the state patrol sees him he will be written a ticket for a very, very large amount of money, but justice is as rare on the road as it is everyplace else, and chances are he’ll cut back into the flow miles ahead.

The traffic jam community also has its own primitive form of communication. If you need to change lanes, the first thing you have to do is get the attention of the driver to your right or left. If he refuses to acknowledge your wave and point, it’s either because he’s day dreaming, agitated, or listening to a self-improvement CD.

A stronger message comes from the person who looks at you, sees you pointing at the space in front of his car, and then turns away. This is a power play. It’s a big world, and his vehicle occupies only a tiny part of it, but you will never, ever get into the lane in front of him and that’s that. He is protecting his territory.

One of the most mystifying things about a traffic jam is that you often come to a resolution without any sign of the original cause. That leaves you troubled, because it reinforces the idea of randomness, that things happen for no particular reason.

Wikipedia has a long-and-winding entry on traffic jam theory and points out that a jam without obvious reason is often triggered by “a pinch” in the road, a narrowing of the highway or an influx of cars up ahead.

But some jams are caused by the butterfly effect. An event takes place that has ripple effects miles away. It may be “an abrupt steering maneuver by a single motorist.”

A wrong turn of the wheel, and a new community is born.

Photo: http://www.flickr.com/photos/danielle_scott/3767637774/