Also, increase public transit options & availability.

No thats communism

I mean, long term that's a fantastic solution. Pretty sure this change can be implemented a lot sooner and a LOT cheaper, and save lives tho.

Limit the speed of private vehicles mechanically, the same way they do with ebikes.

Funfact! Can't be bothered to look it up but I remember reading that lower speed limits actually make people more prone to speed. In most cases, if speed limit is low, people will try their best to hit it and even slightly go over it. In higher speed limits people tend to actually drive slower than speed limit dictates.

This does, however, only apply to express ways and similiar, not city's limits...I mean, people are still gonna try to max their speed but I really don't think we can put it high enough for this to not apply and be safe anyway.

Also, how the hell do americans have this problem when their cities spend 2/3 of the day being locked in slow moving traffic? .-.