For the third year in a row, intercity bus service was the fastest-growing mode of intercity transportation, outpacing air and rail transportation, according to the report, "The Intercity Bus: America's Fastest Growing Transportation Mode -- 2010 Update on Scheduled Bus Service."

Intercity bus operations expanded by 6% in 2010, suggesting that the sector's renaissance is continuing, the report notes.

"This new study from the respected academics at DePaul University confirms that the travel mode shift toward buses is continuing, and it's easy to see why consumers are fast becoming loyal bus riders," American Bus Association President and CEO Peter Pantuso said in a statement. "Buses beat planes, trains, and automobiles in affordability, flexibility, and mobility. Buses are the safest, greenest, most affordable, most hassle-free, and more often the most luxurious way to travel."

Intercity bus service in the United States remained robust through 2010 as a result of rising travel demand, escalating fuel prices, and investments in new routes, the DePaul University researchers wrote.

"These and other factors propelled motorcoach travel to its highest level in years," the report states.

The 12-page report is available at bit.ly/ICBR2010.