Cars have become a major source of personal data collection, with automakers gathering information such as driving speed, night-time driving habits and location and often selling it to data brokers without customers realising. This came to light most prominently with General Motors, which was hit with an unprecedented five-year ban by the US Federal Trade Commission on selling customer data to consumer reporting agencies, after drivers who signed up to its OnStar Smart Driver feature found their information passed to brokers LexisNexis and Verisk, sometimes resulting in higher insurance premiums.

Research backs up the scale of the problem: a Mozilla Foundation study found every major car manufacturer it examined had "horrible privacy and security" practices, forcing customers to accept overlapping data policies covering the vehicle, connected services, smartphone apps and financing. Consumer Reports reached similar conclusions, finding nearly all automakers selling in the US collect and share "driver behaviour data". Unlike smartphones, cars spread data collection across multiple opaque systems, making it hard for owners to understand or control. A proposed US law, the DRIVER Act, would grant owners more access to their data but would still let automakers continue collecting and selling it, drawing criticism from privacy advocates who say it fails to limit excessive data collection at the source.