The study said business travelers are traveling less frequently, which has forced them to stay longer on business trips to get more work done.
The group reported Monday that business trips have declined 22.7 percent from 2000 to 2011, but spending on business trips has increased 3.3 percent.
In hard numbers, U.S. business travelers spent $242.9 billion on more than 576 million business trips in 2000. By 2011, that became $251 billion spent on 445 million trips.
The average amount spent on a trip rose by 33.6 percent, climbing from $422 to $564 during the decade.
"This trend makes sense. We're seeing road warriors taking fewer trips but making the most of them, making more stops and spending more on the road," Michael McCormick, BTA's executive director, said in a statement.