Strong sales of medium duty commercial trucks reportedly are prompting General Motors to add a second production shift at its Flint truck assembly plant.

The Detroit News said the plant, which also builds full-size pickup trucks, currently operates on a single shift, employing 3,370 workers.

However, GM won’t be hiring any new workers to staff the second shift, company spokesman Dan Flores told the newspaper, but will draw from a pool of idled workers and employees from other plants.

It’s not clear, he reportedly said, how many additional positions would need to be filled when the second shift goes into operation in September.

The Detroit News said demand for GM’s medium duty commercial trucks is running far ahead of last year’s sales pace – about 12,500 units have been sold this year – while Flores told the paper that, in 2003, GM sold 20,906 medium duty trucks.

“Commercial trucks are used as a tool by businesses to generate revenue,” Flores reportedly said, “so it’s just one sign the economy is picking up, because businesses are starting to spend more money.”