An Indianapolis commuter spends an average of 41 hours in freeway delays during rush hour each year, according to a study by the Texas A&M Transportation Institute.

That’s the equivalent of a week at work, watching tail lights.

The 41 hours in the Urban Mobility Information Study, released this month and covering 2011, was unchanged from the year before. But it was an improvement from the 49 hours in commuter delays in 2006, when the economy was humming.

The study, which looked at 498 metro areas, said freeway congestion around the country is likely to worsen when the economy rebounds and more vehicles hit the road. 

Indianapolis, the nation’s 12th largest city, ranked No. 23 in delay time per commuter during peak travel periods.

The worst urban area for delays is Washington, D.C., at 67 hours a year.

A new component of the most recent study is the "Planning Time Index," or PTI, which measures how much extra time should be planned for high-priority trips that require on-time arrival.

In Indianapolis, according to the PTI, a traveler should allow 50 minutes for a high-priority commute that normally takes 20 minutes when traffic is light. Doing so would ensure on-time arrival 95 percent of the time.

That’s better than the 57 minutes in Columbus, Ohio; 62 minutes in Louisville; 64 minutes in Cincinnati; and 79 minutes in Chicago.

Such information is useful for planning just-in-time deliveries and time-critical commuter trips such as a ride to the airport to board a flight.

The study looked only at only limited-access roads, such as interstates.

The Indiana Department of Transportation has been rebuilding many of the city’s aging interstates as part of its Major Moves program, which was funded by the $3.8 billion lease of the Indiana Toll Road.

The agency said it’s been limiting lane closures during construction to off-peak times to minimize delays and improve safety. It’s also been adding traveler information displays that can cause freeway motorists to jump off onto secondary streets during interstate logjams.

“While there are many factors that affect mobility, over the past several years, INDOT has been adding capacity to Indianapolis-area interstates,” said Will Wingfield, INDOT spokesman.

Congestion means more than frustration and inconvenience because the average cost of congestion for an Indianapolis peak-time auto commuter per year is $930, according to the study.

That cost was $1,416 in 2006, when traffic congestion was worse.