I live out this way. These aren't local streets like in a city or suburb. It's very rural with houses spaced far apart. Speed limits are 45-55 MPH (70-90 KPH) depending on the road. See for yourself on Street View:

https://www.google.com/maps/@39.5080693,-84.689404,3a,75y,28...

Did you read the article? It was a rural road with a high speed limit.. very common in many parts of the world.

Engineers assumed people wouldn't run into the middle of the street without looking.

So 90% of drivers are incredibly negligent now.

If you slow down to non-lethal speeds for every parallel parked vehicle or obstacle in anticipation of some kid sprinting out from behind it, you might as well walk (not ride a bike, because that problem still exists).

Whilst you're correct that the higher the speed the more likely a fatality, it's also possible to cause death at very low speeds.