When I ride alone, I have an "eye in the sky" monitoring me on Glympse.
If my signal is "too long in one place" that sets off a pre-briefed chain of events.
We (people I ride with) all have the person we want called, with their phone number, listed in our Favorites under ICE. This is In Case of Emergency. This was suggested to us by my daughter-in-law who is a nurse. When the hospital or police are looking through your phone to call someone on your behalf it isnt always clear to them who they should call. All they see are a list of names. ICE tells them who you want them to call.