Truck driver turnover at the nation's large trucking fleets hit 89 percent in the third quarter, the highest level of driver turnover since the first quarter of 2008, the American Trucking Associations (ATA) said Monday.

The third-quarter number represents a 10-percentage-point increase over the prior quarter's 79-percent turnover rate, according to ATA. Since bottoming out at 39 percent in the first quarter of 2010, turnover at large truckload fleets has risen by 50 percentage points, an unprecedented increase, according to Bob Costello, the trade group's chief economist. The driver turnover rate at large truckload fleets has averaged 81 percent so far this year.

The turnover rate at small truckload fleets, defined by ATA as carriers with under $30 million in annual revenue, jumped 10 points to 57 percent, the highest level since the third quarter of 2008, ATA said. Turnover in the less-than-truckload (LTL) segment remained relatively low at 10 percent, a reflection of the generally shorter hauls in this sector of the industry, which allows drivers to achieve a better work-life balance than their truckload counterparts.

In addition, LTL drivers are generally better paid than truckload drivers. According to recent data from consultancy FTR Associates, the median LTL driver's salary is about $58,000 a year, compared with $48,000 a year, on average, for truckload drivers.

For large truckload fleets, the highest turnover level on record was 134 percent, set in the fourth quarter of 2005, which was the tail end of the last great driver shortage cycle and the dawn of what would become a four-year freight recession that devastated the trucking industry. The subsequent decrease in driver turnover from late 2005 to early 2010 was also unprecedented, according to Costello.

In a statement, Costello reiterated ATA's long-held warning that an increase in freight tonnage, combined with the impact of federal safety regulations that will force marginal drivers off the road, will make it even harder for trucking companies to attract and retain high-quality drivers. Proposed changes in driver hours-of-service regulations, which could have the effect of putting more trucks on the road, will further increase demand for good drivers, Costello said.