A decade after Mazda's cars disappeared from Ford Motor's factory floors in Michigan, the Japanese automaker is once again building in the United States ¡ª this time with compatriot Toyota.

When the first Mazda CX-50 crossovers rolled off the assembly line at the joint Alabama plant in January, they were packed with efficiencies hammered out by the two automakers, both known for their cost-cutting smarts and manufacturing prowess.

For Mazda, restarting local production with help from Toyota's deep local knowledge and reputation for reliability is the game-changer it hopes will jump-start sales in the world's second-biggest market.