I read that in the United States they are starting a very useful emergency contact system called ICE (In Case of Emergency). The idea is that since almost everyone carries a cell phone nowadays, we should all store an emergency contact number in our keitai under the name ICE. Then, if a person is involved in an accident, the medical people can check your keitai and easily find the number of a person they could contact immediately on your behalf. If you want to include more than one contact person, just store numbers as ICE1, ICE2, etc.
A paramedic in the U.S. is said to have suggested this system because he often tried to save people involved in an accident, but didn't know who to contact on behalf of the injured person. Parents especially want to make sure that their children's phones have an ICE number so the parents can be contacted immediately if their child is in an accident.
This is a great idea, and maybe Japan can promote this system. It's free and easy to implement if publicized.