Canada

Both is good, because the way our streets are designed are both dangerous and expensive. Narrowing that 40 zone by the school can remove excess road space that now doesn't need to be maintained, cleaned, plowed, or salted. The excess space could be used by school, have trees planted, or be used for alternative transport like transit or bikes.

The roads are currently designed to prioritize driver throughput and provide "wiggle room" for driver error, often at the expense of people outside of the vehicle. Many of the concepts that engineers use to make highways safe were applied to city streets, which in hindsight maybe we don't want our city streets to be designed like highways.

We donthat because we found that wide roads make people drive faster unconsciously. If you design roads badly, people will speed, it will be dangerous. Design roads better and you save lives.

Putting up signs is what most countries have done for decades with exactly 0 results.

A slightly different post had road fatalities in a graph for the US, Canada, and Australia, showing insane levels of road deaths. A secondary graph was added showing the Netherlands at a fraction of those countries, even though the Netherlands is much more densly populated.

Wanna know why? Because the Netherlands does this all the time. Any time an intersection has a lot of accidents, they break up the damn thing and put in a completely newly designed one, and traffic deaths go down. A road has too much speeding? They'll tear out that crap, put in a new road designed in such a way that people will automatically drive the correct speed et voila, speeding stops, Ross fatalities go down

That's why you want to do that

There will always be new people that speed. And people not knowing the place that speed.