Audi is hoping to attract families and groups of travelers to its Silvercar service, through which you can reserve and unlock cars with your phone, by adding its Q7 to the fleet. You can now reserve the SUV in Denver, Fort Lauderdale, Los Angeles, Miami, Orlando, Phoenix and Salt Lake City for rentals starting February 15th. Audi says it will make the Q7 available at its other Silvercar locations from June.