After improving during the first and second quarters of 2006, the driver turnover rate among U.S. truckload carriers jumped during the third quarter, according to the American Trucking Associations (ATA).

Turnover for linehaul drivers at large truckload carriers increased to 121 percent from 110 percent in the second quarter, the ATA reports. Driver turnover at small truckload carriers, meanwhile, jumped to 114 percent from 100 percent. (The ATA defines "large truckload carriers" as those generating at least $30 million in annual revenue. A "small carrier" earns less than $30 million in annual revenue.) This is the first time the turnover rate for small truckload carriers has exceeded 100 percent for four consecutive quarters since the ATA began collecting the statistics in 1995.

"As more and more large carriers try to get out of the long-haul market, more small carriers are filling the gap," says ATA Chief Economist Bob Costello. "This is resulting in higher turnover rates for the segment of the industry that traditionally had a much lower turnover rate."

Year-to-date figures through October 2006 showed that the average length of haul for large truckload carriers had dropped 1.5 percent from the corresponding period in 2005, while the small truckload carriers saw an increase of 12 percent.

The trucking industry is currently experiencing a shortage of about 20,000 long-haul truck drivers. The number could reach 111,000 by 2014 if current demographic and market trends continue.