[This is a completely unsolicited and uncompensated review]Cycling on city streets is a sometimes harrowing experience. While years ago I purchased my own Road ID bracelet so that should something bad happen someone could easily find my brief medical history and emergency contacts, it was only last week that I downloaded Road ID's new self-titled app and took it for a few literal test drives.
The app's purpose is to keep your loved ones appraised of where you are, and in the event of trouble, alert them. By means of email or text message (or both) when setting out on a run, cycle, or hike, the app will send what it calls an "eCrumb" to up to 5 contacts letting them know how long you expect to be out along with a link to where they can track your progress superimposed on a Google map. And if something renders you stationary for 5 minutes, the app will send out a second set of texts and emails to your contacts to let them know you haven't been moving and where you're located (it sets off an alarm before it sends out the alert giving you the option to cancel the alert if you've stopped moving on purpose).
While it's certainly not able to prevent an accident, I'm sure glad it's on and running when I am.