Los Angeles is listed as having the second-worst commute in the country. Washington, D.C., came in at No. 1.
According to the report, commuters in the nation's capital needed almost three hours for a trip that should've taken 30 minutes without traffic.
The new report from the Texas A&M Transportation Institute confirmed Americans spent 5.5 billion hours in their cars in 2011.
San Francisco-Oakland ranks third as the nation's most congested city in 2011. New York-Newark took fourth place, followed by Boston, Houston, Atlanta, Chicago, Philadelphia and Seattle.
On average, Americans needed an extra hour for a trip that would've taken 20 minutes without traffic.
The least-congested city was Pensacola, Fla., according to the report. Commuters only needed nine extra minutes.
Researchers established a formula to measure the amount of extra time needed to arrive on time for an event, a formula that drivers in Los Angeles formulate in their heads daily. The data is gathered from state transportation agencies, private companies and academic entities that monitor traffic issues.
According to the congestion report, traffic in 2011 contributed to 56 billion pounds of carbon dioxide emissions and wasted 2.9 billion gallons of fuel.
The total financial cost of traffic congestion was $121 billion, which translates to an average of $818 per each U.S. commuter.
The institute notes 2005 remains the worst year recording for traffic congestion, but warns that recent improvement may be related to the recession.
Researchers hope these findings will help alleviate traffic in the future by installing policies and projects that will do just that.
The Associated Press contributed to this report.
