By Julie Watts

SAN FRANCISCO (KPIX 5) — Amazon is testing a new service that will unlock your parked car and put deliveries in the trunk.

The company’s in-car delivery service is available in 37 cities including San Francisco, Oakland and San Jose.

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But, there are a few caveats: they won’t just deliver to any car, anywhere.

It’s an all too common complication for Amazon deliveries, packages get stolen right off your porch.

First, Amazon introduced Amazon lockers, then they launched in-home delivery, allowing drivers to drop the packages inside your home.

Now, Amazon is steering its delivery service in a new direction, delivering packages right into your car.

Using Amazon Key, customers can now request in-car delivery.

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Amazon spokesperson Alyssa Bronikowski said, “Some of our customers don’t have a convenient or safe and secure location to deliver their packages…So this gives our customers yet another shipping option…”

Bronikowski says the service is free for Amazon Prime members, but that it only works with certain 2015 or later models of cars with a connected car service like OnStar.

To use the service you have to park your car within two blocks of your home or office, and then request delivery using the Amazon Key app.

CNET reporter Ben Fox Rubin said, “You include things like the make and model of your car, what color it is, what your license plate is, and then the delivery driver will be able to find your car wherever it is parked in that radius.”

Customers choose in-car drop off when placing the order and the they receive an alert on their app the morning of delivery, providing a four-hour window. A final notification comes when the car is locked with the package inside.

Amazon says its drivers will try to hide packages and will put them in the trunk if there’s room.

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Amazon stresses the app and service is secure.