Safety is also more than just "number dead" or "number seriously injured" though that plays a part. Some of it is also "number of incidents that could have been serious" - people walking can bump into each other without any real risk of serious harm (though a mob/crowd crush is a real danger that has to be considered, for example), but many bicycle/pedestrian or bicycle/bicycle incidents have the risk of serious harm.

And "depend on people to do the right thing at the right time with the right skill" should be the absolute LAST fallback - only used when there is no other reasonable option.