Zinger,
Try RoadID for a dog tag type rider's ID,
Road ID | USA's #1 Source for Runners ID, Cycling ID & Medical ID Tags they have them as well as the writs band types and shoe pouches with their ID tag that is laser engraved. You can choose the standard type with whatever contact or medical information you want or the interactive that has a toll free number and your PIN number is engraved on the reverse. First responders or medical personnel can access your medical information as well as contact information you choose. Monica and I both wear them, we have the interactive version. It is inexpensive either way. I have many health issues that an emergency doctor or paramedic/nurse would need to know, this lets them know my drug allergies and specifics about what issues I have. I got my first one when I got back in riding to make Monica feel better about my riding alone out on the roads in our rural area.
Disclaimer: I have no association with Road ID nor do I receive any thing if someone decides to purchase one.
There is a system with a fall or impact sensor that sends out a call to the number of your choice if it is triggered and you do not deactivate it within a given time frame, also. Not sure what it it called, I saw them advertised during various races this spring.
Bill