One of the most important numbers which you should program into your cell phone is that of the correct police agency which covers the jurisdiction around your home.
The 911 system is designed to connect people to LOCAL help. If you dial 911 hundreds of miles from your home, your call will be answered by someone who is hundreds of miles away from the help your loved one needs quickly. We have no particularly quick way of knowing who dispatches the local fire or rescue squad, if it's the Town of Poughkeepsie or City of Poughkeepsie Police who respond to your home address, for example, or what County Sheriff or specific State Police barracks may cover a small town in Podunk, Wisconsin.
Not every area is covered by a large 911 Center, and guess what? We can't dial 911 lest we talk to ourselves. We have to find a local seven digit phone number to contact ANY agency outside of our own. We have speed dials to adjoinging centers and agencies, and a moderate database of varying accuracy to additional PSAPs but there are THOUSANDS of Public Safety Answering Points throughout the United States, and it can take a while sometimes to get help started to an address hundreds of miles away.
Your cell phone is NOT the quickest way to get help in your hometown while you travel. It will connect you to a resource which is local to you as you place the 911 call but that will only start a time-consuming process of notifying the agency which can finally do something for your loved one.
Local police can do a welfare check and know how to get in contact with the agency that dispatches fire and EMS in your hometown. If you are a traveler, one of the single-best programmed numbers you can have in your cell phone is that of your local police department.