Under pressure from U.S. regulators to prevent misuse of personal data from services such as General Motors' OnStar, automakers agreed last week to follow a set of rules intended to guard the most sensitive information.
Under the principles, car companies would give added protection to data that would show where and how people drive and to "biometric" information that would indicate who was in a car at a particular time.
The guidelines underscore that automakers are now part of an expanding category of businesses -- along with marketing firms, software vendors and Internet service companies -- with technology that allows them to passively collect vast amounts of personal information about their customers.
The automakers agreeing to the voluntary rules include BMW, Fiat Chrysler, Ford, General Motors, Honda, Hyundai-Kia, Mazda, Mercedes-Benz, Nissan, Toyota and Volkswagen Group.
Crafted by the Alliance of Automobile Manufacturers and the Association of Global Automakers, two Washington, D.C., trade groups, the rules would take effect for the 2017 model year, with a one-year extension available if engineering changes are required.