A street is made for transporting humans first and foremost. It has sidewalks, driveways to houses are accessed directly from the street, and pedestrians can cross with relative ease, to the point that crosswalks are basically unnecessary.
A road is made for transporting cars first and foremost. There shouldn't be many residential driveways directly leading into a road, there may be sidewalks but they're not going to get used often, and you should rarely see pedestrians trying to cross. Crosswalks are very necessary on roads.
There's no getting around the fact that we need roads. Cars and trucks need ways to move long distanced quickly. The problem becomes when city designers try to mix streets and roads (to make a stroad), leading to massive arteries running through the heart of a residential neighborhood. Proper city design puts roads outside of pedestrian-heavy neighborhoods and fills them with easily and safely walkable streets instead.
There's nothing wrong with an 8 lane road, as long as that road isn't supposed to be used as a street as well.
https://www.strongtowns.org/journal/2018/3/1/whats-a-stroad-...
Interestingly autism rates appear to be higher near freeways (like the ones we put in the middle of cities), yet the anti-freeways-in-urban-cores crowd somehow lacks mindshare compared to antivaxxers.
They've got tons of articles that are right up your alley on the dangers of just putting a 25mph speed limit on a road and calling it a "street".
This one is my favorite: Just Another Pedestrian Killed https://www.strongtowns.org/journal/2014/12/3/just-another-p...