A lot of people on reddit are quite convinced it's World War 1. They reckon the teaser is a soldier in a trench seeing a tank for the first time as it rolls by him.
I've heard that mentioned too. I don't think WW1 really makes sense for BF though, or any modern day FPS. The gameplay would be too slow, the guns, the vehicles, it would all be too cumbersome and outdated. It would be boring, after the initial novelty. It'd be fun at first because it would be so different and new, but long term it doesn't offer enough.
Those red lights look like car lights to me, or some sort of vehicle, which doesn't rule out WW1 but it does make it much less likely.