Japanese automakers Toyota and Mazda have reportedly chosen Alabama as the site of a new $1.6 billion joint-venture auto manufacturing plant, a person briefed on the decision said Tuesday.  

 The plant will employ about 4,000 people and will be built in the Huntsville area in Limestone County, said the person, who asked to remain anonymous because the location hasn't been officially announced. Officials in Alabama are expected to hold a news conference Wednesday afternoon to announce the plant site.