call boxes in urban and suburban areas, leaving them only in areas with minimal cell reception. These telephones are almost always marked by a placard or sign indicating a unique serial number or identifier which allows the authorities to know exactly where the caller is - even if the caller does not know - by having the caller read the short identifier from the placard over the telephone. Some phones are equipped with the equivalent of caller id and the agent receiving the call can identify the location even if the caller cannot. In most U.S. states with roadside call boxes, the call box placard has the route's milepost reading. In California, call boxes are identified by their mileage through individual counties using postmiles for reference. Each box has a 2-letter identifier for the county, followed by the route number, then a 3 or 4 digit number corresponding to the route's post mileage calculated in tenths of miles. Other common locations for emergency telephones Emergency phones can also be found at the ends of bridges or near cliffs which have a history of suicides. These calls are generally routed directly to the appropriate support agencies such as The Samaritans in the UK. They are also occasionally found along the coastline where members of the public may wish to report swimmers or boats in danger at sea. In the UK such phones connect directly to the Coastguard. Emergency phones are also found in elevators where entrapment is very common. These emergency phones connect to a live operator who can help people escape from the stopped elevator. Some car models have an SOS button that connects them to the car company's emergency centre or the emergency services (112) and provide GPS location data. If the car crashes and the airbags inflate, then the emergency phone inside the car activates, even if the occupant(s) cannot reach it. Within Europe the eCall initiative has made this functionality mandatory in all cars sold from April 2018. In some countries, they are also found in places where people may feel vulnerable or unsafe at night. They are commonly found on university campuses, urban parks and housing estates. These are generally linked to security companies who patrol the streets where the phones are located. And on campuses, they typically connect to the campus security or police. Decline Improving coverage of the cellular network in combination with high