Automakers, dealers, and others are experimenting with new ways to provide access to mobility," Michelle Krebs, executive analyst for Autotrader, says. "Now the hot topic is subscription services, many of them offered by luxury automakers."

Think of these emerging all-in-one services, which are paid for by a revolving charge on your credit or debit card, like Netflix or a gym membership. But instead of unlimited streaming or unfettered use of the StairMaster, you pay a set monthly fee for access to different vehicles, along with other benefits. Need a three-row crossover for a long trip? Want a convertible for the summer? These are some of the scenarios that subscription services are aiming to address.

Each of the automaker-specific programs we've detailed here varies in scope, from Care by Volvo's single-car, lease-style setup toBook by Cadillac, which offers access to every model in its lineup and up to 18 vehicle changes per year. Each of them will pick up and deliver the vehicle to your home or office, and each includes free maintenance, roadside assistance, and insurance (provided you have good credit and a good driving record). Most also allow you to cancel or pause your membership at any time. Five of the six services offer vehicles from the current model year, and all but Lincoln Canvas allow you to order or change a vehicle via a smartphone app.

Other than Care by Volvo, these are pilot programs available only in limited markets, and automakers are still experimenting with options and pricing as they learn what their subscribers want. But it appears as though these types of services are only going to expand as the traditional car ownership model continues to evolve.

Book by Cadillac

Cadillac began the industry's first subscription service, starting with its new hometown of New York in February 2017. Cadillac added Dallas and Los Angeles last November, and it's now testing in Munich. Subscribers order a change in model via the Book by Cadillac app.

"For us, Book is very much an experiment and a pilot in which we need to respond as quickly as possible to the member requests and demands that are coming in to us," says Melody Lee, global director of Book by Cadillac.

Vehicles in the Book fleet are equipped to premium trim levels and are administered by companies experienced in automotive events and media fleets. Book members must keep their car at home, so, for example, a subscriber cannot order a vehicle just for a weekend trip, though Lee says that Book might consider such a variation as Cadillac's service evolves.

"We definitely have more demand than we anticipated and more demand than we can easily satisfy at this time, which is a good problem to have," Lee says. "Interest continues to grow every day. We're operating in the lower hundreds at the moment, in terms of vehicles and members."

Lee also says that the average age of a Book member is 41, some 20 years younger than a traditional Cadillac buyer through a dealer. So far, although the sample size is still small, Book appears to be exceeding Cadillac's expectations.

bookbycadillac.com

Initiation Fee:$500

Monthly Fee:$1,800 (cancel at the end of any monthly cycle)

Vehicle Availability:Limit of 30 consecutive days with the same vehicle, up to 18 trades per year

Locations:New York City, Dallas, Los Angeles, and Munich, Germany

Models:All, including ATS-V, CTS-V, and CT6 plug-in hybrid or with Super Cruise (the vintage CTS-V wagon is available in L.A.)