THE SLOWDOWN IN AUTO SALES in the United States is likely to lead to shutdowns of production lines by car makers, such as this production line at the General Motors assembly plant in Arlington, Texas. / BLOOMBERG NEWS PHOTO VIA GETTY IMAGES/MATTHEW BUSCH
SOUTHFIELD, Mich. - Auto workers may be getting some extra time off around Independence Day, but they won’t be celebrating. They’ll know it means sales are weak and that profits - and profit-sharing checks - could be shrinking. Manufacturers used to shut plants for a week or two in July for maintenance and to keep…