Heavy truck maker Peterbilt Motors is recalling most of the more than 500 hourly workers it laid off during a 10-month lockout that ended last July.

According to Associated Press (AP), the move comes as the truck market improves – the company brought back 150 workers in January and is recalling another 150 from March 8.

“I would expect everybody back soon, maybe in the [autumn],” United Auto Workers Local [branch] 1832 president Mike Pardue told AP.

The plant cut production by two-thirds in 2002 but will increase it 50% when the workers rejoin the assembly line next month, AP said, citing plant manager Larry Vessels. The factory currently assembles 20 large trucks a day.

Vessels reportedly attributes the rise in sales to a better economy and the growing acceptance of new, more expensive engines that meet stricter federal air quality standards.

PACCAR Inc., the Bellevue, Washington-based parent company of Peterbilt, predicts sales will rise 10 to 15% this year, Associated Press said.

Those returning next month are reportedly long-time employees who haven’t worked at the plant since all 750 hourly employees were locked out after the contract between Local 1832 and the company expired in September 2002.

The union offered to continue working under the former contract, but the company declined the offer, AP added.

The report said union members overwhelmingly approved a contract 10 months later that called for higher wages and higher health insurance premiums and about 250 workers returned on July 1.