First it was in-home deliveries, now Amazon wants to deliver goods directly to the trunk of your car.

The ecommerce giant today announced a partnership with General Motors that will open up in-trunk deliveries to 2015 (and newer) connected Chevrolet, Buick, GMC, and Cadillac vehicles with an active OnStar remote access subscription, in addition to Volvo vehicles with an On Call account.

Back in October, Amazon announced its new Amazon Key in-home delivery service, which is powered by a camera and smart lock, and the company then went all-in on the smart home by acquiring smart doorbell maker Ring for more than $1 billion. The Amazon Key In-Car service represents an expansion of that initiative, enabling Prime subscribers with one of the aforementioned compatible vehicles to have a package delivered directly to their car while it’s parked in an easy-to-access location.

The service is open to 37 cities across the U.S. from today, though the company had given early access to a number of people in the buildup to this launch, and made this video here.

While deliveries are generally limited to goods that can fit inside a car trunk — such as groceries, some electronics, and daily essentials — Amazon said larger packages may also be left in the vehicle’s main cabin space. That is an interesting admission, given that parcels visible to passers-by on the street may be more attractive to window-smashing thieves.

How it works

Drivers must connect their Amazon Prime account to the associated online account for their vehicle, which is done through the Amazon Key mobile app. If you live in an area…