The risks may be much higher for women, but in most places the base rate is still very low. "Assaulted by a stranger on the street" is actually fairly low in the risks for almost anyone: the vast majority of assaults, especially sexual assaults, are perpetrated by someone the victim knows.

(This also doesn't necessarily mean that such concerns are irrational, just that the risks are not so high that you should expect every woman going out for a run in the dark is eventually going to be assaulted)