Speeding is an inherently human problem, you cannot solve the human, you can only trick the human into solving the problem for you, i.e. scaring them and making speeding actively risky for their own car.

Ultimately, on top of traffic calming, we need way better public transit and making driver’s licences harder to acquire with longer, more rigorous training. That way, driving is not an obligation and those who don’t want to drive or should not be driving do not have to drive. Not everyone was meant to drive.