Trucking rates, which are near historic lows, are heading for a big rebound.

The questions are, how big—and how soon?

The trucking industry has dramatically shrunk in the past two years, due to record-high fuel prices in 2008 and the recession of 2009. The number of national truckloads shipped with freight from only one customer—the biggest part of the industry—fell 15 percent from 2008 to 2009, according to the American Trucking Associations.

Terrance Pohlen, an associate professor of logistics at the University of North Texas, said he believes trucking companies will not add capacity in the form of new trucks and drivers until they know that demand has returned in a significant, sustained way. The improving economy, meanwhile, will push demand higher for trucking services.

“Rates,” Pohlen said, “will go through the roof.”

Pohlen, who is also director of the University of North Texas’ Center for Logistics Education and Research, predicts that prices for trucking freight will rise in the high single digits on a percentage basis. He said it will happen by or during the third quarter, the peak season for moving goods for the holidays.

“The pendulum is swinging to the carriers,” Pohlen said. The only question is how fast and how high it will swing.

“The carriers will be the ones with leverage at the end of the year.”

To experts like Pohlen, the issue of what will happen to rates boils down to a simple formula of supply and demand.

“We saw a historic drop in supply,” said Bob Costello, chief economist of the American Trucking Associations. “It was masked by an even more historic drop in demand.”

Costello said there is no single way to measure the supply of trucking services, but added that there are some proxies.

For instance, on a national basis, average revenue per mile was off 15 percent from the peak in early 2008 to the trough in the middle of last year.

Costello added that he suspects Pohlen’s thesis about rates rising sharply is right on the money. But not everyone is so sure.

“I can build a case for (Pohlen’s) point of view,” said Richard Metzler, chief commercial officer at Dallas, Texas-based Greatwide Logistics Services. “I can also build a case for the alternative point of view. I’m somewhere in the middle.”

“You have a sustained recovery—or you don’t,” Metzler said.