Tanner's back, and apparently he can release an astral projection. During Ubisoft's press conference we learned of Driver: San Francisco's "Shift" feature, in which Tanner may float in suspended time from one car to another, continuing the action from it.
Demonstrating the game, Ubisoft's Martin Edmondson said that Tanner's been involved in a terrible accident and put in a coma, and it is from this state that he can project out of a crashed vehicle for example, and into a completely different one, continuing the action from it.
Integrating that kind of game feature into the story of what has been a pretty straightforward guns-and-cars narrative will be challenging. Does this mean that the entire story being told is Tanner's dream? As described, it sounds like a type of God-mode coming to a police drama. It's innovative, and it's intended to be the means through which you explore an open world "full of life and full of missions."
Given this is an Ubisoft game, it sounds somewhat like Assassin's Creed; instead of Desmond in the Animus adventuring through his memory, it's Tanner in a coma doing the same with his subconscious.
Considering the 1970s motifs of Driver: San Francisco the coma and the strange metaphysical journey of a police officer, I first thought of the TV show Life on Mars. And while critically applauded, that TV show had only two seasons in the UK, and just one in the US.