Many children did not survive car crashes because they were allowed to wander about in a car. Many nowadays do survive with seatbelts and safer car seats for the smaller children.
I’m not against seat belts, that’s for sure. Even as a kid in the 70’s I always wore one. Which is why it fascinated me how we got to that point from cars not even having seat belts in less than twenty years.
From talks with my grandfather about driving in Pittsburgh in the 20’s I think 20MPH might be a generous estimate of the average speed that was possible. Between cobblestone streets and the gawdawful terrain you were probably lucky to get that. He said the Model T did not really have enough power to handle the hills around here. Had to turn them around and take them up in reverse, like having front wheel drive.