Your car knows more about you than you think.

DETROIT (AP) -- 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.

Car data is about to become big business. A new report from consulting firm McKinsey says automotive data could be worth $450 billion to $750 billion globally by 2030. Automakers, insurers, high-tech firms, city planners and advertisers are among those who could use data to refine services. Drivers could share data in exchange for navigation systems, or they could pay extra for perks like a parking spot finder.

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

Q: Which cars collect data?

A: 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.

For example, General Motors Co. will have 12 million connected vehicles by the end of this year worldwide, which it says is the most for any automaker.

Q: Do I own data that's collected?

USA Today -- There are plenty of reasons to rent a car, from leaving an unreliable car behind on a vacation to getting around on a business trip. But there's a real hidden danger when doing so that you may not even realize — one that potentially puts you and your family at substantial risk.

Rental companies continually upgrade their fleets with newer-model cars, which means many now have the latest infotainment systems, which let you connect, or "pair," your smartphone via Bluetooth with the car. This lets you take calls over the car's audio system, dial from the center console, get directions or stream your music. Others include a USB connection so you can do all that and charge your phone.

When you connect your gadget to a car with Bluetooth, the car stores your phone number to make it easier to connect later. It also stores your call logs, including any contacts you dialed. Just one problem: All that information is saved inside the system and just sitting around for the next renter to find.

First, we all know that returning a rental car usually happens at the last moment. You're in a hurry and the flight won't wait for you. But give yourself an extra 10 minutes to remove your personal data from the car.

Simply go into the car's settings (it will vary for every car make and model) and locate your smartphone from the list of previously paired Bluetooth gadgets. There should be an option to delete your phone. That should wipe the call logs and saved contacts. Better yet, look for an option to clear all user data or do a complete factory reset. Talk to the employees at the car rental place if you can't find these options.

Read the rest of the story here: http://www.usatoday.com/story/tech/columnist/komando/2015/07/03/komando-car-rental-mistakes/29614165/