[throwaway2037]

Hongkong has a lot of raised pedestrian infra in the central business district. It is difficult for people with "reduced mobility" (disabled, old, baby cars, etc.) to navigate. As a second order effect, it has turned street level into somewhat of a Mad Max zone where cars drive as fast as possible knowing there are no pedestrians to worry about.

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.

[Symbiote]

England, especially London, has removed a lot of those railings in the last decade, for exactly this reason.

(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.)