The issue there is that everyone has an inflated sense of their ability to drive at speed, and it's "other drivers" that are the problem.

Growing up in Australia, my dad pointed out two things to me, learning to drive: 1) that in my state at that time, you were required to drive at the maximum speed that was: within the limit, appropriate to the conditions and your ability to control the vehicle, and 2) that if it was to directly and imminently avoid an accident, a driver is permitted, for the minimum time possible, to ignore any road law (i.e. you cannot be cited for crossing over into oncoming traffic if it was to avoid traffic about to hit you. It was also commonly used for people cited for speeding while passing another vehicle - you'd appeal, and say "While I realize that I am still required to obey the speed limit when passing, as I was doing so, the vehicle I was passing adjusted its speed putting me in a situation where I felt the safest course to avoid an accident was to accelerate past them and then return to the speed limit").

But yes, as someone who was both a paramedic for 14 years, I've seen more than my fair share of drivers who think that they are safe (which, to be clear, is general commentary - I obviously don't know you).

Also, people generally self-regulate down to a speed that "feels safe" for the road at hand. Sometimes this itself causes problems (the HUGE suburban streets near me constantly have speeding cars, because again, the street is huge and wide lanes make people confident to drive faster) but again, the issue there is that you need to make the road narrower, and then drivers will naturally slow down.

These mechanisms among others are much more effective at traffic calming rather than putting up more damn signs to clutter things up, and hiring more cops. But of course fixing streets costs money, and police issuing fines generates it, so it's not shocking that most municipalities go with option B.