Amazon has partnered with GM and Volvo on its new In-Car Delivery service for Prime members, which launched this month in 37 U.S. cities. Prime members with eligible GM or Volvo cars simply select In-Car Delivery at checkout. Amazon couriers do not have direct access to the car -- the unlock command is issued through the car's connected systems (i.e. OnStar or Volvo on Call) as part of an authentication process. This service complements the Amazon in-home service launched last year.