Most of the places I do my riding are out of cell phone range and have minimal traffic. (My personal record is 135 miles before the first car passed me.) Since I do a fair amount of my riding either by myself or on a tandem with my wife, we use a Spot. It allows select people to track our location and gives us four other pre-set messages we can send, one of which calls in the search and rescue. We may upgrade to one that allows us to send unique text messages when the service term is up next year.