Canada

Bigger problem is people are bad judges of risk while driving. People's perception of how fast they can safely travel doesnt line up with their actual abilities.

Roads are built with a design speed 20kph higher than the posted limit because that's the margin left for safety. That covers things like balding tires, like a distracted driver not paying attention, or bad weather.

There can be some changes (ie the number of municipalities that insist on a 4m wide lane is RIDICULOUS for residential roads), but the vast majority of the factors that make it "safe" to drive that speed are there for a reason.

You get less frustrated on a road with no posted limits anywhere that jsut naturally nakes you want to drive a speed that feels safe, and happens to be 30kph.

Nah, I don't believe that's what happens, because we've had so many single vehicle crashes because people have no idea what feels safe. They drive like they're behind a screen, like a video game. Except that screen is a windshield and their face can go through it.

Someone going 100km/h in a 40 zone is an asshole who has no regard for human life. No road design will make them care, and the solution to that problem is to not allow certain people to drive.

Equip vehicles with behaviour sensing tech, and if someone is routinely driving aggressively, not stopping when they should, speeding, and parking in areas that put others in danger, they should lose their license.