Traffic jams are forcing frustrated Twin Cities commuters to waste more time behind the wheel.

And that growing congestion has pushed the metro area up to No. 16 on the list of America's Worst Traffic Cities, according to the seventh-annual Traffic Scorecard Report, released this week by a global traffic-tracking company called INRIX. The survey relies on transponders in 100 million vehicles to provide real-time traffic flow data.

The survey found that traffic levels in Minneapolis-St. Paul were up 17 percent last year compared with 2012 and that commuters here spent 14 percent more time on the roads than the year before.

For many metro-area motorists, that meant they wasted 24.5 hours in 2013 — four more hours than the year before — sitting behind the wheel in congested traffic. And drivers who use some of the metro's most notorious bottlenecks end up wasting as much time in their cars as motorists in some of the country's most congested cities.

For example, on southbound Interstate 35W from downtown Minneapolis to Crosstown Hwy. 62, motorists experience delays averaging 12 minutes a day trying to make the 7-mile trip.

More stress, too

Don Zenanko, who delivers live metro traffic reports from the Minnesota Department of Transportation's traffic control center, said he's seen the mounting stress.

"There are more road-rage incidents,'' Zenanko said. "People are calling 911 to complain about someone who cut them off or they're shaking their fist or they're throwing items at cars. There's a lot more of that. A lot more shorter fuses.

"Congestion impacts people in different ways. I like to sit in a car and listen to music while I inch up and down the road," he said. "Other people are little more intense. A lot of people dread sitting in traffic. They dread having to go 2 mph down the freeway when they should be going 50 to 60 mph."

Others see the congestion as simply part of the package that comes with being a big city.

Depending on the methodology, rankings put the Twin Cities between the 13th- and 16th-largest U.S. metro area, said David Levinson, a civil engineering professor at the University of Minnesota. "The fact that we're ranked 16th in congestion seems about right," he said.

Levinson said demographic trends are helping to mitigate road congestion.

"Travel times are declining in the U.S.," he said. "People are aging. Old people don't travel as much, and young people don't travel as much as what young people used to. Fewer kids own cars. The big picture is that that the total amount of travel peaked in the U.S. a few years ago and it's been declining ever since. We have some ups and downs during any given year depending on the price of the gas and whether the economy is doing a little bit better or not. Certainly [congestion is] more than in 2009 during the depths of the recession."

Jim Bak, who wrote the INRIX report, said the clogged roads in the Twin Cities may be the result in part of what's going right in the metro area — an unemployment rate that is well below the national average, a growing economy and a shift in which more people — especially new college graduates — are moving to the urban core and closer to jobs. Stable fuel prices, consumer confidence in the economy and harsh weather also played a factor, he said.

"We are seeing more freight traffic, and that is what drives increases in congestion," Bak said. "That is not good for motorists, but your 401(k) and stock portfolio is better than it was three years ago" in part because of that increased commerce.

Best and worst rush hours

For those who have to navigate the roads, the INRIX study found that gridlock on metro freeways is at its worst on Tuesdays from 8 to 9 a.m., when trips take 14 percent longer than normal, and on Fridays from 5 to 6 p.m., when trips take an average of 20 percent longer. Friday mornings offered the best rush-hour commutes, followed by Mondays from 8 to 9 a.m.

Metro traffic experts say road construction projects and winter weather can make some years worse than others.

The extent of congestion on a certain stretch of road is sometimes a subjective view, Zenanko said, and one easily skewed when a multiple-car crash on a sunny day backs up traffic for miles.

Levinson and others are quick to point out that Twin Cities drivers could be dealing with much worse.

In Los Angeles, home to the nation's most-congested roads, drivers spent 64 hours sitting in traffic, an increase of five hours from the previous year, according to the INRIX study. In Honolulu, the nation's second-worst city for traffic, drivers sat behind the wheel 60 extra hours last year, while in No. 3 San Francisco it was 56 hours.

And, Levinson points out, there's more good news for the Twin Cities. The average speed of travel in the metro area is the fifth-highest in the country.

"You sit in traffic at a particular bottleneck, but then when you're moving on the freeway, you're driving at 55 mph,'' he said. "And when you're driving on arterials, you're driving at 45 mph, and that's better than most metro cities."

mlsmith@startribune.com 612-673-4788

tim.harlow@startribune.com 612-673-7768