Denver is the 15th most congested city in America, according to a new study about traffic congestion. The Inrix National Traffic Scorecard analyzes the trends affecting the countrys most congested cities and the worst traffic bottlenecks. Denver moved up one spot to 15th in 2009 from 16th in 2008 and up from 18th in 2007. The top five congested cities are Los Angeles, New York, Chicago, Washington, D.C. and Dallas. Colorado Springs was ranked 88th on the list, up from 91st last year.The Inrix data shows Denver has the worst rush-hour congestion on Friday evening between 5 p.m. and 6 p.m. saying commuters pay a 20 percent "travel tax." Travel tax is the company's way to equate the extra time needed in traffic compared to free-flowing traffic with a 10 percent tax equaling 10 percent additional trip time due to congestion.The overall traffic congestion is worse in the afternoon hours between 3 p.m. and 7 p.m. than the morning hours between 6 a.m. and 9 a.m.The Monday morning blues might make you feel down, but the most congested day of the week for the morning commute is Tuesday. It is followed by Monday, Thursday, Wednesday and Friday. Mondays are the best day for the least congested ride home. The most congested day of the week for the afternoon commute is Friday, followed by Thursday, Wednesday, Tuesday and Monday.The study also looked at the freeways with the worst areas for bottlenecks. Topping the list is the section of northbound I-25 between the Emerson and the Santa Fe exits. That is followed by: Southbound I-25 at the Park Avenue West exit Northbound I-25 at the US 36 exit Westbound I-270 at the Vasquez Boulevard exit Westbound I-70 at the Washington Street exit Eastbound Sixth Avenue at the I-25 exit Southbound I-225 at the Sixth Avenue exitNationally, the Inrix data shows the 30 percent drop in congestion that began in late 2007 and early 2008 is over. The company states the level of congestion will largely be shaped by the rate and pace of economic recovery, job growth and any severe fuel price shocks. The report states, "In the short-term, economic activity and the price of fuel are the most important factors driving changes in overall congestion and delays at a national level. The past several years have seen perhaps the most volatile mix of fuel price swings in generations, along with the scariest economic downturn in at least 25 years."Inrix predicts what happens in 2010 and beyond to congestion will largely be shaped by the rate and pace of economic recovery, in particular the rate or lack thereof of job growth on a regional and national scale.Some of the key national traffic congestion scorecard findings include: Morning congestion is down overall and evening congestion is up 30 minute commutes average 22 hours of annual travel time delay nationwide Stimulus projects are increasing off-peak congestion, up 25 percent from 2008 75 of the 100 largest metropolitan areas still have less congestion than in 2006In 2009, the nations Travel Time Tax was 8.85 percent. This means that during peak driving times a random traveler on a random trip on the roads analyzed in the 100 largest regions in the U.S. took an average of 8.85 percent extra time than if there was no congestion. From an individuals perspective, this translated into a national average 22.1 hours of additional total travel time annually for a one-way commute that takes 30 minutes when uncongested.If you want to drive in the cities with the least traffic you have to go to Florida. Fort Myers ranks 100 on the list and Lakeland, outside Tampa, ranks 99th.To see the entire list and to get more information visit the Inrix Scorecard site.