An emergency telephone is a phone specifically provided for making calls to emergency services and is most often found in a place of special danger or where it is likely that there will only be a need to make emergency calls.
Although it is difficult to determine when and where the earliest highway emergency phones were developed, undoubtedly one of the earliest examples were the freeway phones developed in Western Australia in 1966. This system was developed by Alan Harman, an employee of a Western Australian security firm, Central Station Security Company, Electronic Signals Pty Ltd, who came up with the idea after reading of a pile-up on the Kwinana Freeway. The newspaper article mentioned that assistance had been difficult to provide to those involved in the pile-up. The system Harman envisaged was a series of telephone units in a box on a short post, spaced every 160 metres (0.1 mi) on Perth’s freeways. Picking up the handset would trigger an alarm in the Main Roads control centre and police, fire or ambulance could then be determined by the caller. Harman developed the system with the approval of the Main Roads Commissioner and Chief Engineer, by adapting the existing design of communication facilities used at the security firm in which he worked.
Emergency telephones are commonly found alongside major roads throughout the world. In the United Kingdom, orange "SOS" call boxes are spaced every 1.6 kilometres (1 mi) on all motorways as well as some major "A" roads, with roadside markers indicating the nearer phone. Emergency telephones were installed every 0.25 miles (400 m) on all limited-access highways ("Freeways") throughout Southern California in the United States as far back as the 1970s. In Melbourne, Australia, emergency telephones were introduced on metropolitan freeways in 1976, originally on the Tullamarine, South Eastern and Lower Yarra (West Gate) Freeways. On Italian "Autostrade" ("Motorways"), "SOS" emergency phones, generally coloured in yellow, are found spaced every 2 kilometres (1.2 mi).
As cell phone use continues to increase, the need for emergency telephones declines and they are being phased out in many cities. In California, freeway call boxes were used about 98,000 times in 2001. That number dropped by 80% to 20,100 times in 2010, or about 1 call per box per month. The cost of freeway call boxes for the Service Authority for Freeways and Expressways (SAFE) program in the San Francisco Bay area is $1.7 million annually.