U.S. transportation companies will continue to outperform the broader stock market in 2011 amid a boom in global exports, according to Edward Yardeni, chief investment strategist at Yardeni Research Inc.

“Global exports are absolutely booming and the U.S. benefits from that and our railroads do extremely well and so do our airfreight companies,” Yardeni said in an interview today on Bloomberg Television’s “Surveillance Midday” with Tom Keene.

The Dow Jones Transportation Average, the 20-company gauge of railroads, trucking companies and airlines that includes FedEx Corp. and United Parcel Service Inc., has returned 24 percent this year, doubling the return in the Standard & Poor’s 500 Index.

Of the 19 Dow Transportation companies that reported results since Oct. 7, 74 percent have topped analysts’ per-share earnings estimates, according to data compiled by Bloomberg. Sales increased 17 percent for the group.

The broader U.S. stock market will increase based on earnings growth, he said.

“I’m just betting on all of the billions of people out there that want cars, apartments and refrigerators,” New York- based Yardeni said.