Automakers and brands have begun to look outside the traditional ownership model to expand their business opportunities, and one of the more popular areas of expansion include car sharing services. Audi had previously waded into car sharing with its Audi On Demand service, and now, it's launched a high-end version in Beijing, China, called Audi On Demand+.

Like Audi On Demand, which launched as a trial service two years ago in San Francisco, California, the new On Demand+ operates on the same basic concept: Users select and book the car they want through a smartphone application, and pay the stated rate. However, the two services differ in several ways.

Audi On Demand does not include unlimited mileage, and rates per mile vary by car. On Demand+ includes unlimited miles and insurance coverage, and a concierge service drops off and picks up the user's chosen vehicle. Audi's regular On Demand service isn't that flashy, and users must wait for curbside concierge deliveries or park the car in designated drop-off areas to be picked up. Audi On Demand also charges by the day, while On Demand+ rental periods start at 4 hours and extend as long as 30 days.

Audi didn't give its pricing for the new On Demand+ plus service in China, but it's likely not inexpensive. In 2015, official Audi On Demand rates in San Francisco started at $165 per day for an Allroad crossover utility vehicle and quickly soared to $1,295 a day for an R8 Spyder.  With Audi On Demand+, the brand simply says Audi Sport models and premium sedans will be made available for booking. 

Back in the United States, Audi is likely gearing up to refine the On Demand experience. Earlier this year, it purchased Silvercar, a premium car-rental company that operates a fleet of Audis out of select U.S. airports. In the future, we'll likely see Audi On Demand and Silvercar work more closely together. In China, Audi says it would like its On Demand+ service to expand into more major cities in the next few years.