The awards were presented Sunday, the first day of media previews for the show. The show opens to the public Saturday.
The winners were picked by a group of 49 full-time automotive journalists from the U.S. and Canada. Finalists had to be new or substantially redesigned from the previous model to be eligible to win the award, which has been granted at the show for 14 years.
Both vehicles are made by General Motors Corp., meaning that the winners came from a single manufacturer for the second year in a row. Last year's winners were the Honda Motor Co.'s Ridgeline pickup and Civic car line.
The Aura beat two other finalists in the balloting for North American Car of the Year, the Honda Fit and Toyota Camry. The journalists picked the Silverado as well as the Ford Edge Mazda CX-7 crossovers as finalists.
The North American honors have been given annually since 1994. Jurors scrutinize each vehicle's design, safety, handling and innovations. Judges also consider driver satisfaction and value.
U.S. brands have won the car award seven times, with Japanese brands taking top honors three times and European brands winning four times.
Domestic brands have fared better in the truck awards, taking them nine years, while Japanese brands have won three times and the Europeans have won twice.