The root of road rage: Humans are territorial, and the car is an extension of a person's territory, AAA says. Image

In a new survey on which of 25 major U.S. cities have the most aggressive drivers, Miami dropped from 1st to 7th, Reuters reports. The Top 3:

New York Dallas/Fort Worth Detroit

Hey! My city should be No. 1. @#%$@#!

Yes, and it's exactly that attitude that gives us road rage.

While no statistics are kept specifically on road rage, the National Highway Traffic Safety Administration (NHTSA) estimates that aggressive driving causes about a third of all crashes and about two-thirds of automobile fatalities. And studies show it's not just total jerks who become enraged.

But why does getting behind the wheel transform the meek and mild into raving, dangerous idiots?

What causes road rage?

Simple: "Human beings are territorial ... The car is an extension of this territory," according to AAA. True that. Plus, as a 2008 study found, humans crave violence just like sex. Watch out particularly for wide-faced men, known to be more aggressive than others.

There's another factor: Negative actions play out bigger than positive acts, University of Chicago researchers say. Feeling slighted can have a bigger effect on how a person responds than being the recipient of perceived generosity, the researchers found.

"For instance in driving, if you are kind and let someone go in front of you, that driver may be considerate in response. But if you cut someone off, that person may react very aggressively, and this could escalate to road rage," said University of Chicago psychology professor Boaz Keysar. "Small slights could escalate to unbelievable, irrational feuds."

There's even a disorder thought to be behind extreme cases of road rage among some people: "intermittent explosive disorder, which is "characterized by recurrent episodes of angry and potentially violent outbursts — seen in cases of road rage or spousal abuse," wrote Ronald Kessler Harvard Medical School and colleagues.

Intermittent explosive disorder "has been found to be much more common than previously thought," Kessler and colleagues wrote in the Archives of General Psychiatry in 2006. "Depending upon how broadly it is defined, this disorder affects as many as 7.3 percent of adults, or 16 million Americans, in their lifetimes."

Attacks resulting from the disorder "are out of proportion to the social stressors triggering them" and aren't related to other mental disorders, according to the Diagnostic and Statistical Manual of Mental Disorders. "People with this disorder overreact to situations with uncontrollable rage, feel a sense of relief during the angry outburst, and then feel remorseful about their actions," Kessler and colleagues wrote.

The flipping of the bird comes to mind. But it's not clear to me how the remorse is ever manifested. I saw a woman shrug once just after she almost ran me over.

Times have changed

Americans can all be proud that "road rage" is a term that is believed to have originated in the United States, according to research by AAA. And while it's been around for decades, it is changing.

Road rage has gone high-tech. When AAA surveyed 526 motorists in 1995, the biggest road-rage related complaint: tailgating. In the new survey, the biggest gripe: other drivers talking on cell phones.

Of course there's a difference between lousy driving (talking on the cell phone makes you as bad as a drunk driver), aggressive driving, and road rage. But on the road, where we're all being a little territorial, little things can escalate.

In an ongoing LiveScience poll, 67 percent (as of this writing) say cell phones should be banned while driving.

A final note for the high-and-mighty who can't stand road rage:

It's quite possible you're as bad as the next guy. A decade ago, researchers found that drivers who think they don't have a problem with anger while driving can be just as angry and dangerous on the road as those who know they are aggressive drivers. On that note, check out Edmunds.com's list of 10 tips to avoid road rage, including my favorite: Your car is not a therapist.

In The Water Cooler, Imaginova's Editorial Director Robert Roy Britt looks at what people are talking about in the world of science and beyond. Find more in the archives and on Twitter.