The U.S. Government Accountability Office looked into practices at General Motors, Ford, Chrysler, Toyota, Honda and Nissan.
It also examined data storage practices at the nation's two largest GPS manufacturers, Garmin and TomTom and navigation app designers Google Maps and Telenav. While the report did not specify practices at individual companies, the GAO said the automakers collect data at times to assist customers with traffic updates, emergency roadside assistance and to track stolen vehicles.
The report said none of the companies are selling the data collected from drivers but that most motorists do not know what information is being tracked and cannot opt out of the data collection programs, the Detroit News reported Tuesday.
The report states the companies can "track where consumers are, which can in turn be used to steal their identity, stalk them or monitor them without their knowledge. In addition, location data can be used to infer other sensitive information about individuals such as their religious affiliation or political activities."
Sen. Al Franken, D-Minn., the senator who chairs a Judiciary subcommittee on privacy, requested the GAO report and said the results lead him to believe automakers need to do more to protect customers' privacy.
"Modern technology now allows drivers to get turn-by-turn directions in a matter of seconds, but our privacy laws haven't kept pace with these enormous advances," Franken said in a statement. "Companies providing in-car location services are taking their customers' privacy seriously -- but this report shows that Minnesotans and people across the country need much more information about how the data are being collected, what they're being used for, and how they're being shared with third parties."