Traffic

New data show that in 2008 traffic congestion in the nation's cities declined by 30 percent, the result not of new roads or transit, but of modest declines in VMT.

Forbes has released its list of the most congested cities in America. Los Angeles, New York, Chicago, Dallas and Washington D.C. top the list.

The patterns of leafcutter ants are not unlike vehicular traffic patterns, yet they never get stuck in traffic or get in accidents. This article shows what we can learn from them, and why we probably never will.

In an effort to help officials and tourists in Washington D.C. deal with inauguration crowds, researchers at the University of Maryland have created a "four-dimensional" map that tracks traffic and road conditions in real time.

In the first of two guest posts, UCLA researcher Eric A. Morris blogs on the logic behind congestion pricing.

At lunchtime, traffic in Tysons Corner is even worse than during the morning commute, causing officials to launch a lunchtime shuttle to keep more cars off the road.

On Monday, Gothamist revealed the winners of a contest to redesign the traffic-clogged intersection of 4th Avenue and 9th Street in Brooklyn.

A new study shows that noise pollution on the streets of San Francisco is putting nearly one in six residents at risk for heart disease, high blood pressure and other stress-related illnesses.

A new study finds that sometimes closing roads can improve traffic flow by forcing people to make alternative choices to the shortest route.

Next American City reviews a new book called Traffic: Why We Drive the Way We Do (and What it Says about Us) by journalist Tom Vanderbilt, which follows in the footsteps of Freakonomics and Blink.

A new report from the Metropolitan Planning Council pegs the annual cost of congestion to the Chicago region at $7.3 billion.

Commuters on Ireland's N11 expressway were surprised to find that the cause of a massive traffic jam was a monkey on the loose.

City officials in Lockhart, near Austin, consider allowing golf carts on arterial streets.

Despite efforts by politicians to enact policies that reduce congestion, the biggest improvements in traffic reduction appear to be tied to rising gas prices and tolls, according to data from New York.

A new study suggests that getting freight onto trains and off of trucks would have a significant impact on traffic.

A year after a new freeway was completed in Southern California, traffic data shows increased use. Officials plan to widen the freeway to handle the increased load.

The video website YouTube is home to a growing number of clips that document traffic conditions in cities around the world.

Some planners hope that driverless car technology can finally put an end to traffic jams.

The Transit Coalition's Bart Reed and USC planning Professor Peter Gordon debate transit and traffic in L.A. in this five-part point-counterpoint series.

In Sao Paulo, Brazil, planners are challenged with untangling traffic jams that stretch for over 120 miles.