2015 was one of the auto industry’s best sales years. General Motors, Toyota, Ford, Fiat Chrysler, and Nissan all reported higher annual sales Tuesday. Industry analysts estimate car manufacturers sold 17.5 million vehicles nationwide last year, which would be a new record. Autotrader senior analyst Michelle Krebs tells WDET’s Pat Batcheller what drove sales in 2015. Click on the audio player to hear the conversation.