Errands, Coffee Cause Traffic Jams

July 29, 2008— -- The honking. The swearing. The obscene gestures.

Welcome to navigating a traffic jam, an activity millions of Americans take part in every day.

While most people do what they can to avoid the daily grind, Tom Vanderbilt sought it out and found that maybe a little nonviolent road rage could be a good thing.

After three years of sitting in traffic jams around the world, he penned "Traffic: Why We Drive the Way We Do (and What It Says About Us)," which takes a look at traffic myths and facts.

Among his findings? Sorry gentlemen, but men are worse drivers than their female counterparts. They drive more aggressively, drink more, don't wear seatbelts as often and are more likely to be involved in major accidents, though women can claim responsibility for most minor accidents.

But to be fair, women cause more congestion on the roads because, studies show, they run more errands. And your morning cup o' joe? That also causes brake lights in a phenomenon known as the "Starbucks effect."

While riding shotgun on a recent hair-raising New York commute, Vanderbilt pointed out to ABC News correspondent Jeremy Hubbard that some intersections have two Starbucks, one on each corner -- the company's way of bending with traffic patterns. It's a far cry from a bygone era when commuters would make their coffee at home and eat breakfast before leaving the house.

Vanderbilt's research has also uncovered all kinds of little-known facts about what we do behind the wheel. Did you know that, on average, we mess with the car radio 7.4 times per hour?

Or that if you wait for the best parking spot at the grocery store, statistically, you almost always take longer getting inside than drivers who grab the first spot they see. And when we switch lanes because another is faster, in the long run it really isn't.

Never mind the headaches and stress caused by sitting in traffic: Can all that time behind the wheel put us at risk for cancer? Studies show that men have skin cancer more on the left side of their bodies, theoretically because they spend so much time in the car.

"Just your arm and the windshield, and if, you know, you go to Britain, I think it's in the right side," Vanderbilt said, "but men suffer that more than women, because men drive more miles, they spend more time in the car."