Truck driver turnover is increasing steadily and exceeding pre-recession levels at both large and small truckload fleets, propelled by a combination of higher freight volumes and tighter regulations, industry experts have said.

The turnover rate for truckload drivers at large fleets rose to 89% in the third quarter, from 79% in the second quarter, the fourth straight increase, American Trucking Associations reported.

Driver turnover among larger fleets rose modestly in the second quarter, but declined slightly at smaller fleets that traditionally have greater success in retaining drivers, American Trucking Associations reported last week.

Truck-driver turnover rose from historic lows during the fourth quarter of 2010, and is likely to rise further this year as fleets seek more drivers to meet growing freight demand, American Trucking Associations reported last week.

Driver turnover rose measurably for the first time in nearly four years during the second quarter, American Trucking Associations reported, as increasing freight volumes gave drivers more options.

Driver turnover — or churn — at large truckload carriers hovered near its all-time low in the fourth quarter of 2009, coming in at 44%, American Trucking Associations said.