Modern cars are a “privacy nightmare” and have questionable security practices, according to a report by the tech company Mozilla.

While cars have increasingly been described as “computers on wheels” because of their advanced technological capabilities, the report says that the 25 car brands it reviewed failed their tests. That has made them “the worst category of products for privacy we have ever reviewed,” it said.

Poor practices

Every car brand reviewed collected more data than necessary and used that information in ways that went beyond operating their vehicles and managing customer relationships. 

“They can collect super intimate information about you — from your medical information, your genetic information, to your ‘sex life’ (seriously), to how fast you drive, where you drive, and what songs you play in your car — in huge quantities,” the report said – referring to an in-depth article on how data is collected. “They then use it to invent more data about you through ‘inferences’ about things like your intelligence, abilities, and interests.”

In addition, 76% of car companies sell personal data and 92% gave drivers little or no control over their data – only Renault and Dacia said that customers could request to have their information deleted.

Little choice

No company performed well, and Tesla got the most privacy warnings because of its inbuilt AI systems. The company said that it was possible to request that the company stops collecting data, but that “this may result in your vehicle suffering from reduced functionality, serious damage, or inoperability,” according to the report. Customer consent and understanding is made difficult by the complexity of the vehicles and jargon-laden privacy documents.

The industry has come under scrutiny for such practices. For example, the California Privacy Protection Agency said in July this year that it planned to review the way that vehicles collected and used data from features such as built-in apps, sensors and cameras.

Data ownership is not clearly defined in EU law and the European Commission is working on rules to ensure fair access to the information car makers collect. Fortune Business Insights calculate that the connected car market could grow as much as €400 billion by 2023.