Before Driver: San Francisco, Ubisoft tasked Sumo Digital with making the next Driver game. Unseen 64 has unearthed details and concept art on the abandoned project, which apparently would have involved the Bay Area and tons of explosions. Split/Second: San Francisco?
I'm a sucker for reading about cancelled games, and wish more game companies were willing to open up about them. It seems like I'm reading about potential movie projects that eventually fall through all the time, but everything stays tight-lipped in video games. Most of the time, anyway.
Sumo Digital actually worked with series creator Reflections on another Driver game for PSP called Driver '76, which was set two years before Driver: Parallel Lines, the third game in the franchise. Driver 5 would have been another collaboration between Sumo Digital and Reflections, but the game never moved past pre-production. Driver: San Francisco went forward, even though it's clear a Driver game in San Francisco was an idea kicking around.
More information on Driver 5, a game we'll never play, is available over at Unseen 64.