This year, Americans have been buying cars and trucks at an annualized rate of more than 14 million vehicles, the strongest performance since early 2008. Automakers have rebounded since demand plunged during the 18-month recession that began in December 2007, which caused production cuts and mass layoffs and forced both GM and Chrysler into bankruptcy. Government data show that motor-vehicle production contributed half of the first quarter's annual pace of 2.2% economic growth. The auto resurgence -- from assembly lines and dealerships to steelmakers, freight lines, and loan providers -- signals the US is headed for solid growth, says Joseph Carson, director of global economic research at AllianceBernstein in New York. Contributing to the auto sales revival are rising employment, an improvement in consumer confidence, and a thaw in lending.