鶹ý — CHICAGO— Reserved seats, more routes and luxury amenities helped increase intercity bus travel in the U.S. again in 2014, reports a new study from DePaul University’s Chaddick Institute for Metropolitan Development. Bus service providers added more than 100 new daily services in 2014, resulting in a 2.1 percent increase in over last year.

"Once people switch to the bus, they often become frequent users, in part due to the generous allowances bus companies provide to change departure times,” said Joseph Schwieterman, director of the Chaddick Institute and co-author of the study. “Travelers appreciate this flexibility, which that has long vanished from air travel."

The number of schedule options for bus travelers is growing faster than other modes of travel, researchers found. While bus service grew, Amtrak train-miles held constant, and the number of airline flights diminished by 3.5 percent.

Expanded bus service in Florida by Megabus and the Southwest by Greyhound helped connect even more U.S. cities via bus, researchers found. “Apart from the lightly populated Rocky Mountain States, the U.S. is now mostly covered by city-to-city express carriers that offer nonstop service between cities less than 300 miles apart," Schwieterman said.

The number of operations by city-to-city express carriers has almost doubled since the start of the decade, rising from approximately 589 in 2010 to 1,066 in 2014. Overall, U.S. intercity bus daily operations (akin to flights in airline travel) grew from 4,309 to 4,399 last year.

"The intercity bus industry continues to invest in new services at a time when Amtrak mostly holds steady and airlines reduce the number of daily departures," Schwieterman said.

Luxury offerings and new amenities for business travelers also were unveiled in 2014. In addition to mid-range lines adding reserved seating, luxury buses operating between Austin and Dallas offer a private boardroom. And, first-class service on the East Coast includes direct service to hotels. New travel-booking websites also have made it easier for travelers to compare rates and fares, and buy tickets.

The study, “Adding on Amenities, Broadening the Base: 2014 Year-in-Review Intercity Bus Service in the United States,” was co-authored by Schwieterman and research associates Brian Antolin, Gary Scott and Martin Sellers. The report is available at .