https://www.sciencedirect.com/science/article/abs/pii/S09257...
Turns out there are other ways to make cycling safe. One could argue that helmet wearing might make it even safer, but we are talking about optimizing a number that is already very low.
I’ve been to Stanford before and the campus is pretty car free. It is big and mostly flat, so most students have bikes to get from one building to another, but you aren’t speeding around or anything, it’s a very Dutch biking experience.