As I said before, I think that especially in wealthy countries, this thing is mostly useful as a parable, whose message is: Look how much money people will spend on infrastructure whose sole purpose is to avoid taking any space from motorists.
I think that if the thing has any application, it’s probably not in Europe or North America. There are several reasons:
This thing is massively capital intensive. The little rail-like running-ways in the street are the least of it, and the fleet is the second-least. The stations are massive elevated structures, with a level for the bus platform another level above for pedestrian circulation across it. Existing bridges would almost all need to be raised. Countries with high construction costs will find this a barrier.
It will serve stations located on expressways, which tend to be bad places for the pedestrians that the bus will attract and disgorge. The only solution to this is massive grade separation, leading to a continuous pedestrian plane at the station level, well above the street. This leads to urban design that essentially abandons the ground plane to cars and rebuilds an entire pedestrian city above it.
The vast raised pedestrian plane was a hot idea for about 15 minutes in the 1970s, giving us London’s Barbican, Paris’s La Défense, Los Angeles’s Bunker Hill, etc etc. Today, most European and North American urbanists hate these places and insist on solving problems on the ground plane, though of course the pendulum could swing again. But it’s much more common and accepted in East Asia, and to some extent in former Soviet countries.
There’s also the problem that if you build this thing in an existing dense city, you are building it right outside of someone’s window. So you probably need a political structure that can make and enforce highly controversial decisions, as opposed to the kind of deference to public protest that prevails in most Western democracies.
You really have to redesign big districts around this thing, which is another big barrier unless we are talking about entirely new areas. A high pedestrian plane only works if the idea is shared by many surrounding buildings.
Where this thing connects with underground subway lines, your mezzanine for this elevated thing is at least four stories away from the subway’s mezzanine. This requires high-volume vertical circulation, which no inventor has ever really cracked. Elevators are really inefficient at high volume, and escalators are really slow at it.
The nature of this technology makes it hard to demonstrate at the right scale. There is a basic conflict between “huge capital expenditure” and “demonstration of new technology.” It’s the same problem that monorails and maglevs and “Personal Rapid Transit” and many other cool ideas have had. Inventors need places to do demo projects. But it’s not smart for a city to agree to be Version 1.0 of something, while also spending billions on the assumption of its permanent success. This is how cities end up with stranded transit assets that can become net barriers to good transit (see Scarborough RT, Toronto, or the airport maglev in Shanghai, etc etc.)
Having said that, if anyone can pull this off at scale, it’s probably China, which seems to tick all the boxes I’ve identified. They have sufficiently centralized decision making, low enough construction costs, ability to do things at scale, and relative indifference to Western aesthetics that this thing requires. They are also building entirely new districts, which offer the best possibility for actually organizing a place around the correct elevated ground plane.
So yes, it may happen, and it may do some good. Which is entirely consistent with it being, on a deeper level, ridiculous.