Modern cars are collecting more data than ever, raising privacy concerns. The Mozilla Foundation says cars are the worst product category for privacy. They collect data from interactions, onboard services, and connected devices. This data is often shared with insurers and data brokers. Drivers should be aware of what their car collects. Privacy4Cars offers a service to check automakers' data practices. Drivers can adjust settings to limit data sharing. Opting out may affect features like navigation and roadside assistance. When selling a car, a factory reset is recommended to protect personal data.