This happened at my university at about the same time that Heinlein wrote this. A girl stepped out from behind a shrub, directly in front of a moving car. She knew that the car had to stop (even though there was no crosswalk there), and was too stupid to figure out that it would not do so if it was impossible.
There was a fuss about whether the car might have violated the 20 MPH campus speed limit, and have been going as fast as 25 MPH. However, a car going 15 MPH would have still hit her.
We had a 20 something young lady last fall who was walking at night, in the rain, wearing her I-Pod headphones with a hoodie pulled over her head, and strolled right around the activated warning gates, lights and bells and into the path of an oncoming light rail train.
There is nothing you can do for someone like that.