Modern cars collect vast amounts of personal data including location, weight, facial expressions, and driving habits through sensors and internet connections. Car companies sell this data to insurance companies and data brokers, potentially raising insurance costs for drivers. A new federal law will require biometric monitoring systems to detect impaired driving, expanding data collection further. Privacy protections are minimal, with most consumers unaware of the extent of surveillance. Experts recommend disabling data sharing features, avoiding phone connections to car systems, and reading privacy policies to protect personal information.