Our daily commute transforms us into faceless, brainless and occasionally ruthless creatures who may bear little resemblance to our out-of-car selves.

Out there, on I-85, we cruise in a comfortable anonymity that enables us to behave pretty much any way we want. For long and critical stretches on I-20, we switch off our brains, forgetting that we're in sole command of a 4,000-pound machine that can kill people. And we do things out on I-75 that we wouldn't dream of doing back in our Kennesaw subdivision.

"If you're driving in someone else's neighborhood, who cares? You'll never see them again," author Tom Vanderbilt says. "And the highway is sort of the ultimate in anonymous, nasty behavior. Certainly no one lives on the highway, so there's no incentive to act human at all."

Vanderbilt's new book, "Traffic: Why We Drive the Way We Do (and What It Says About Us)," explores the psychology, mechanics, sociology and history of traffic. It goes on sale Tuesday. In three years of research and travel around the world, Vanderbilt made a number of startling discoveries and observations, including:

> You can look away from the road for just two seconds before you start to lose track of what's in front of you.

> People search for something in the car while driving —- sunglasses, change for the toll, whatever —- an average 10.8 times per hour.

> " 'Road rage' lends a clinical legitimacy to what might simply be termed bad or boorish behavior elsewhere. 'Traffic tantrums' is a useful alternative, nicely underscoring the raw childishness of aggressive driving."

> Why do people rubberneck at accidents? Morbid curiosity, of course, but also the belief that we should not miss out on something that other people get to see.

> The English roundabout is far safer than the standard American four-way intersection.

> Caesar declared a daytime ban on travel by chariots and carts because traffic was so heavy in first-century Rome. The satirist Juvenal wrote that it then became impossible to sleep at night because of the clatter in the streets.

 WALTER CUMMING / Staff
Illustration of an automobile with teeth

 WALTER CUMMING / Staff
Illustration of an automobiles with teeth