I expect we will see a low-frequency supplemental band carved out to ensure low-bandwidth connectivity in cellars and carparks before too long. You won't be streaming movies over it, but they'll be able to talk to that car.
With all the incumbent users lower than 600 MHz, I don't know how realistic that is. They've already been pushed out of 600/700/800 MHz. Those pushed out won't want to invest in another move.