The Check In feature in the new version of iOS will save lives and deter assaults. If you haven't checked it out, it's got a little complexity, but the basic idea is that you pick a sort of "safety partner." Using Check In (inside Messages: tap +, then tap Check In), you pick someone and then set a timer or choose a destination (including travel time and a margin). For a timer, your iPhone asks you to respond at the end of the time. If you don't in 15 minutes, it alerts your Check In buddy.
With a destination, your iPhone tracks your progress. If you stall for more than a reasonable time along the way or head the wrong way, you're alerted. If you don't reply, Check In alerts your friend/relative/etc. It also alerts them if you trigger Emergency SOS at any point. If the timer expires and you've checked in with your phone, that's it; if you reach your destination, your friend is informed.
@bb1a99d2 does not work on WiFi - only mobile data. :(
@bb1a99d2 Others have done this for a while; my current employer links it with their EMNS and will have campus security alerted for those moving around a university campus. Off campus, you need to provide a mobile number.
Having it in the OS opens it up to everybody. Definitely worth encouraging those walking around alone to use it.