Statistics like these guide us like orange cones through Traffic: Why We Drive the Way We Do (and What It Says About Us), Tom Vanderbilt's just-published joyride in the often surprising landscape of traffic science and psychology. Vanderbilt, a journalist in Brooklyn, New York, describes Finland's income-based ticketing policy, which has resulted in one of the lowest crash rates in the world—and in a $71,400 fine for an Internet entrepreneur going 43 in a 25- mile-per-hour zone. He wonders if China's riotous thoroughfares might owe something to Chairman Mao's fondness for revolt. Vanderbilt tells us what we long suspected but could never prove: drivers really do take longer to leave a parking spot when they know you're waiting, and almost none of New York City's pedestrian "walk" buttons actually work. At the same time, though, he introduces previously unimagined hazards: there are roads in Idaho where it is possible to skid on a layer of living katydids.

To trace the origins of our present transit messes, the book meanders through ancient Pompeii and Rome's chariot-choked streets, which grew so clogged that Caesar banned daytime travel "except to transport construction materials for the temples of the gods" and a few other purposes. Careening carts and coaches menaced 18th century London, where traffic fatalities surpassed even "immoderate quaffing" as the leading cause of death. But Vanderbilt spent much of his research time cruising our modern roadways. He hung out at the Los Angeles traffic center on limo-clogged Oscars night in 2006 (naturally, the Best Picture that year was Crash). And he learned lessons from Disney's FastPass system, meant to relieve congestion at Space Mountain. Describing various traffic theories, he compares vehicles to rice, croquet balls and cannibalistic crickets (anyone who has been on the New Jersey Turnpike sees how each of these makes sense). He also introduces a handy automotive vocabulary. The "dilemma zone" is the moment when the light has turned yellow and you can't decide whether to hit the brakes or floor it. "Highway hypnosis" is when you space out driving. "Digineckers" photograph car wrecks with their cellphones. "Hedonic adaptation" explains why commuters won't leave the exurbs to cut down their drive: basically, they get used to having big houses.

Traffic itself, Vanderbilt points out, is a language of its own—a set of rules that unites a culture while allowing for individual flair. American drivers tend to stand up for their rights: when tailgated, we may well passive-aggressively brake instead of abandoning the left lane to speeding scofflaws. But "in some ways it's hard to talk about the American driver," Vanderbilt told me. "The culture shifts with the state, the population shifts, the laws shift. " Drivers die in Montana in disproportionately high numbers, in large part because of the state's rural roads, elevated drinking-and-driving rates and formidable speed limits. (The single deadliest road, on the other hand, is Florida's U.S. 19.) Driving differences also span continents. Parts of northern Europe have an almost prim driving style, while in some Asian cities, it's trial by fire, or at least, exhaust fumes. A Shanghai intersection that looks as pretty as a kaleidoscope pattern from a 13th floor hotel room proves to be, upon closer inspection, a fearful crush of cars, mopeds and pedestrians. In Delhi, India, Vanderbilt is warned that his "reflexes" are not up to local driving; indeed, posted signs say "Obey Traffic Rules, Avoid Blood Pool" and "Don't Dream, Otherwise You'll Scream."

"India generates the most impressions, because basically you have people living within feet of the traffic stream, sleeping, cooking, selling things, and then of course there are the cows," Vanderbilt said. " You could never have highway hypnosis in India."

Vanderbilt says he decided to write about driving on a whim, in the midst of performing a daring highway merge maneuver. But lucky for him, plenty of people have devoted their professional lives to the study of traffic—building driving simulators and robots, gaining parking insights from the foraging habits of barn owls and wearing women's wigs in order to observe the effect of cyclist gender in bike-car interactions. Is there a more relevant subject? After all, Americans spend even more time driving than eating (though increasingly these activities are combined: Vanderbilt notes that some 22 percent of restaurant meals are now ordered through a car window). And yet driving can be a profoundly isolating experience. We can't speak directly with other drivers on the road, or even make meaningful eye contact if we're going faster than 20 miles per hour. Horns are misinterpreted, turn signals botched, middle fingers brandished.

Since his book's debut this summer Vanderbilt has been besieged with e-mails from as far away as Japan. He never realized how desperate people were to discuss this cloistered aspect of collective culture. "Everyone really wants to talk about the left lane," he confided. He's become a driving psychiatrist of sorts, a traffic confessor.

With so much stress, chaos and, yes, death (the average person driving 15,500 miles a year for 50 years has a 1 in 100 chance of dying in a car crash) associated with traffic, perhaps it's a good thing that the vehicles of the future will be more able to fend for themselves with sophisticated censors and computers. Or so Vanderbilt predicts. Eventually driving will be a much less visceral activity: with cars in control, everyone can just sit back and enjoy the ride.