ARLINGTON, VA. — The annualized turnover rate for U.S. linehaul truckload fleets of all sizes spiked in the second quarter, breaking the 100 percent ceiling, according to the American Trucking Associations (ATA) quarterly Trucking Activity Report.

This is the first time in more than four years that the turnover rate has broke 100 percent.

Large truckload fleets saw their driver turnover rise 16 percentage points to 106 percent. That's the highest level since Q4 '07.

Meanwhile, smaller truckload fleets saw turnover jump to 86 percent in the second quarter, a 15-point jump from the Q1 2012.

“We continue to see steady, albeit sluggish, growth in freight volumes, which increases demand for drivers,” ATA Chief Economist Bob Costello said. “That, coupled with continued pressure on fleets to improve their safety records as a result of regulatory oversight changes, is increasing competition among carriers for drivers with clean histories.

“We have been contending that the driver shortage is by and large qualitative, rather than quantitative,” Costello continued.

“Despite some estimates, I believe that in terms of raw numbers, the trucking industry is currently short somewhere in the range of 20,000 to 30,000 drivers. However, if we continue to see growth in freight volumes, we can expect that number to rise in the near future, exacerbating the qualitative shortage and creating a quantitative one.”

Turnover rate for less-than-truckload fleets averaged 9 percent in the second quarter, up from 8 percent in the previous quarter.