The data your car collects and who can use it

Your car knows more about you than you think.

Newer cars that connect to the internet can collect vast amounts of data about drivers, such as where you went to dinner, if you broke the speed limit, or if your seat belt was buckled.

When you buy a car, you cede data control to your car company. Most automakers say they won't sell information without an owner's consent. But they're not legally required to inform you if they do.

Here's a primer on the emerging issue of connected-car data:

Question: Which cars collect data?

Answer: Just under 20 percent of new cars sold globally now can be linked to the internet, according to BI Intelligence. That figure is expected to reach 75 percent by 2020.

Q: Do I own data that are collected?

A: That's unclear. Under federal law, drivers own data stored in event data recorders, or "black boxes," which monitor vehicles in a crash. Police and insurers need a driver's consent - or a court order - to get that information. But there are no laws addressing data collected by automakers through vehicle internet connections.

Q: How do automakers use the data?

A: It depends on the vehicle and the manufacturer. Some turn data into notifications. Cars can automatically signal for help if an air bag deploys, for example. Some will send a message if oil needs to be changed or a vehicle is being recalled.

Q: Can automakers sell data without my knowledge?

A: They could, depending on language in owners' manuals. But under voluntary principles established by the Alliance of Automobile Manufacturers in 2014, most agreed to get permission before sharing anything about a driver's location, health, or behavior with third parties.

Q: Can I stop an automaker from collecting my data?

A: Most automakers let owners opt out, but that's usually buried in fine print, says Khaliah Barnes, former associate director of the nonprofit Electronic Privacy Information Center, who now works on privacy issues for the federal government.

For example, some GM owners' manuals tell people about data storage, but they must track down separate policies to learn more, Barnes says.

Q: Are there benefits to sharing data?

A: Yes. Upon a driver's request, GM will send driving data to insurance companies like Progressive and State Farm to see if the driver qualifies for lower rates. OnStar will send coupons to your phone for businesses along your route.

Tesla collects data to improve cars via software updates.

Q: What's the downside to sharing data?

A: Insurance companies could require drivers to let them monitor driving before they grant a policy. They could see if you go fast around curves, accelerate too quickly, or if you don't wear a seat belt. That could raise rates. You could also get overwhelmed with unwanted coupons.