(NBC) -- While you're cursing the traffic you're idling in on your way to work, not only time is being wasted, a new study released Tuesday shows.
An annual study of national driving patterns reveals that Americans spent 5.5 billion additional hours sitting in traffic in 2011.
Traffic jams on the way to or from work ate, on average, 38 hours of commuters' lives that year, up from 34 hours the year before, the study found. That's nearly four hours longer than the average workweek.
The Texas A&M Transportation Institute's report found Americans are adapting to road congestion by allowing, on average, an hour to make a trip that would take 20 minutes without traffic. The Urban Mobility Report also says clogged roads cost Americans $121 billion in time and fuel in 2011.
The report is one of the key tools used by experts to solve traffic problems. But the institute advises that every community has unique challenges and require different, multi-faceted approaches to solving congestion.
Washington, D.C., where drivers spend 67 hours per year in traffic, was the most congested urban area for the second consecutive year, followed by Los Angeles, San Francisco, New York and Boston, the researchers found.
Traffic congestion reached its peak in 2005, when drivers spent an average of 43 hours a year in traffic.
"Prior to the economy slowing, congestion levels were much higher, and we really expect to see the conditions of congestion ... really go up as the economy improves," Bill Eisele, a TTI researcher and the co-author of the report, told Reuters.
The reduction in congestion had more to do with job losses than any coordinated effort by cities to move to alternate forms of transportation, Eisele said.
He said that peak congestion nationwide was on Friday from 6 p.m. to 7 p.m. while more than one-third of all delays occurred in the middle of the day.
The report found that 60 percent of delays occurred on streets and 40 percent on highways.
The congestion brought with it a hefty price tag: Traffic congestion cost American motorists $818 each in 2011 - more than is spent on Christmas presents - from wasted gasoline to lost productivity to increased vehicle maintenance costs, the study found.
Drivers on average wasted 19 gallons of fuel in 2011, the report found.
Clearing vehicle crash sites more quickly, better synchronizing of traffic signals and improved notification of traffic delays to motorists would all ease congestion, Eisele said
"As this report demonstrates, travelers are paying the price for this inadequate response," Eisele said.
Monday, June 17 2013 2:24 PM EDT2013-06-17 18:24:00 GMT
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