Traffic delays will increase 65% and the number of congested lane-miles on urban roads will rise by 50% over the next 25 years, according to a study released Thursday.
Los Angeles will continue to have the longest delays, with trips during peak hours taking nearly twice as long as they do when roads are free-flowing.
By 2030, drivers in 11 metro areas Atlanta, Baltimore, Chicago, Denver, Las Vegas, Miami, Minneapolis/St. Paul, Portland, San Francisco-Oakland, Seattle-Tacoma and Washington, D.C. will be stuck in daily traffic jams, according to the study by the Reason Foundation, a nonprofit think tank.
Traffic congestion in smaller cities will worsen substantially over the next two decades.
To prevent or relieve this severe congestion, U.S. freeways and arterials need 104,000 additional lane miles of capacity, at a total cost of $533 billion over 25 years, the report said.
The full study, "Building Roads to Reduce Traffic Congestion in America's Cities: How Much and at What Cost?," is available online at