As far as I can tell, the general consensus among urban planners is that building pedestrian overpasses/Skyways/skywalks is a _really bad idea_.
They suck pedestrian life away from the ground plane and surrender it to cars, which has all sorts of second order effects.
The ground level becomes darker, and more dangerous with less "eyes on the street". Car focused transport planners are more bold to increase traffic volume (with increases in pollution/crashes/noise). Businesses on the street struggle.
> Isolating large vehicles from fragile human beings is the best engineering solution.
It may be the best _engineering_ solution (don't get me wrong, I love some Brutalism and textured concrete), but it's usually a horrible outcome for street life. The best solution for a healthy, livable street is to build large spaces for pedestrians and cyclists, reduce car speeds to 30kph/20mph, or remove cars altogether.
I'm not sure that kind of design can work everywhere, but it can perhaps be an option in some places.
Related: Hongkong also uses (awful) metal gates to keep pedestrians caged into sidewalks. Again: It makes drivers more aggressive. When I visited Shanghai, a lot of sidewalks blended into the street which had an interesting effect: Drivers were much more cautious because people frequently flowed into streets.
Last comment about lower car speeds: I recently drove on Japan (100% grade separated) expressways in Tokyo, Kawasaki, and Yokohama. At first, it seemed so damn slow. Mostly 80 km/h, but many places slowed to 60 km/h. Really, 60 km/h feels like crawling on an expressway! Always two lanes each direction. Very few on/off ramps. However, after driving more than an hour, I could see the effect: Traffic flowed very smoothly, even in very busy areas. I can only guess this is intentional design.
(I was amazed just how similar the street level design of Hong Kong was to London when I visited. Of course, it had a century of being constructed to the same standards and regulations.)
Literally raise the 'pedestrian ground level'. I've also realized that construction cranes and other things that need to poke up through that level should do so by rotating and shipping away the cap segments that the pedestrians walk on and blocking off a work site while in use. Though they'd do that anyway for safety.
What a lovely and fair idea. Make the ones who use muscle power to climb up and down, while not even sligtly inconveniencing those who can accelerate by just changing the angle of their feet.
I wonder if people who think this is okay walk sometimes or become one with their car already.
We'd generally be better off with most of the traffic lights in town being replaced by humped pedestrian crossings on the legs of roundabouts, except for the two major thru roads. But for some reason, the county council has been putting in signalized intersections (with ~12-16 light poles) for small, 30kph intersections (max one lane each direction).