Neat idea but it violates the 'kiss' principle on several points. I'll believe it when I see it, in spite of the fact that 'building will commence soon'.
It is simple in a way. It's an alternative to building another deck on top of the road for light rail to run along. Probably cheaper and less devastating to communities that it runs though.
How will the drivers deal with a vehicle that is in their perpetual dead angle ? How will the driver of the 'urban train' see the vehicles he's moving over and make sure that none of them get crushed at intersections in case traffic somehow got blocked?
China has some history of 'grand announcements' which are then not followed up on, and a few that they did follow up on that failed fairly spectacularly. We'll see if this one works out, I'm sceptical but who knows, maybe it will work.
The three gorges dam is also still holding up in spite of lots of nay saying so I'll give them the benefit of the doubt.