Have you ever been stuck in traffic and thought of all the things you could be doing that would have been more productive? A new study has confirmed your suspicions.

A Reason Foundation report released Thursday found that reducing traffic congestion and improving travel times could boost the Salt Lake area's economic output by up to $700 million a year.

The report examined the impact that population growth and longer commute times will have on five key locations across the Salt Lake area by 2030. They are the downtown business district near EnergySolutions Arena, Brigham Young University, Fashion Place Mall, American Fork and Salt Lake City International Airport.

Of those locations, the Reason study said the biggest economic gains would come from eliminating severe congestion around suburbs such as American Fork.

"Essentially what you do … is to allow people … to significantly increase the reliability of their travel times," David Hartgen, co-author of the report, senior fellow at the Reason Foundation and professor of transportation at the University of North Carolina at Charlotte, told the Deseret News.

The Reason Foundation is a nonprofit think tank that develops nonpartisan public policy research promoting choice, competition and a dynamic market economy, according to its Web site.

Hartgen said that among the eight cities in the study, Salt Lake had the least traffic congestion and had the fewest road capacity needs over the next 20 years. The study took an in-depth look at traffic and economic growth in Atlanta; Charlotte, N.C.; Dallas; Denver; Detroit; Salt Lake City; San Francisco; and Seattle.

"Reducing traffic congestion by 10 percent improves productivity by over 1 percent. One percent may sound small, but in a city like Salt Lake, it can mean hundreds of millions of dollars in economic gains," Hartgen said in a release. "The biggest gains come from enhancing mobility around suburbs, universities and malls."

He added that relatively modest expenditures, such as removing bottlenecks in high-congestion areas throughout the region, could significantly reduce travel times, particularly if the congestion is relatively concentrated geographically.

Hartgen noted that shorter overall travel times result in lower buffer times, "the time you stick on the front of your trip in order to be sure that you arrive on time."

"For some trips, that buffer time is very small," he said. "No one really cares when you arrive for the beer party. But for work, an airport flight or school, the buffer times are a substantial portion of travel times."

The study stated that adding road capacity around the rims of cities and investing in suburban accessibility often offers very good return rates.

The report estimated the cost of relieving congestion woes at $1.2 billion for Salt Lake City, compared with $10 billion for Denver.

The report found that urban areas with less congestion, such as Salt Lake City, would not experience dramatic improvements in productivity — Denver's could rise by 31.6 percent, compared to Salt Lake's 1.4 percent, it said. But Salt Lake would still benefit as the accumulation of improvements in travel flow boosted the overall regional productivity.

"You have to relieve those bottlenecks because those bottlenecks are actually costing you money," Frank Gray, Salt Lake City director of community planning and development, told the Deseret News.

He said the Utah Department of Transportation and the Utah Transit Authority are working diligently to focus their planning efforts on controlling congestion in the area's fast-growing suburban cities like American Fork.

"They are always shifting and balancing the dollars between the core areas (like Salt Lake City) and the suburban areas," he said.

"You're seeing a greater and greater tilt to the suburban areas."

e-mail: jlee@desnews.com