[HPsquared]

Ah yes the "ball pit" option. Sure it probably works but it costs a lot and reduces the utility of the roads.

[david-gpu]

It increases the utility of the streets for pedestrians and cyclists by, you know, not getting them killed.

Many traffic safety measures cost very little to implement, or even retrofit. You can look up what has been done in Hoboken, NJ -- no pedestrian fatalities since 2017.

[HPsquared]

Fair enough for dense urban areas, I suppose.