Emergency Call

Synonyms / Other Terms Used

Emergency Phone, Emergency Telephone, SOS Call

Category

Regulations, Safety Signs, Safety Action, Fire Equipment, Health and Safety

Message / Function

To indicate the location of or direction to a control that when activated makes an emergency phone call (eCall) to a call centre for getting help in case of an accident or other emergency.
To indicate that the emergency phone call is in progress, from call initiation to hang-up and to indicate a corresponding system status.

	Source	Description
	ÖNORM A 3011	Telephone handset or receiver next to letters SOS
	ÖBB 2007	Telephone handset or receiver next to letters SOS
	Tern	Telephone handset or receiver next to letters SOS
	StVO D	Telephone handset or receiver next to letters SOS
1)	Unknown	Telephone handset or receiver next to tilted text SOS
	ISO 7000	Telephone handset or receiver next to letters SOS
	W-RSFI	Telephone handset or receiver in red, next to letters SOS
	W-RSFI	Telephone handset or receiver next to letters SOS, both in red on white background
	W-RSN	Telephone handset or receiver next to letters SOS
	RVV 1990	Telephone handset or receiver above letters S.O.S.
	RS UA	Telephone handset or receiver above letters SOS
	Parks Canada	Letters SOS next to telephone handset or receiver, all in white on green background
	SADC	Telephone handset or receiver next to letters SOS on yellow background inside circle surrounded by brown background
	Québec	Telephone handset or receiver next to letters S.O.S.
	Eco-Mo Foundation	Letters SOS, telephone handset or receiver below, all in white on red background
	ISO 7010	Telephone receiver (profile), first aid cross, all in white on green background
	SABS ZA	Telephone handset in front of five concentric circles, green background
7)	Unknown	Telephone handset in outline, exclamation mark on the right
	U.S. National Park Service	Blue telephone handset on white background
+)	BS 5378	White telephone handset on green background
*)	Collins	White telephone handset on red background
2)	ON Testdesign	Hand in plan view with one finger extended and pointing downwards towards dot with letters SOS on the right
3)	ON Testdesign	Hand in plan view with one finger extended and pointing downwards towards dot, text ALARM below
4)	ON Testdesign	Capital letters SOS
5)	ON Testdesign	Capital letters SOS arranged diagonally from bottom left to top right
6)	Unknown	White square with bold circle inside, text ALARM on background below

Note: Some of the examples shown above were mirrored horizontally to contrast differences.

Discussion

Many pictograms for the message Emergency Call/Emergency Telephone shown in the table above are variations of the rendering used for the corresponding road sign that can be found in the 20. Convention on Road Signs and Signals with the reference number F, 17. Wikimedia Commons offers a specific collection of emergency telephone road signs covering more than ninety variations, some of which are just text based. Several other documents found show additional image contents to indicate the location of a control used to make an emergency phone call. But since the end of the last century numerous pictograms in use have a similar image content, and the concept based on a telephone handset or receiver close to the letters SOS has become widely accepted. Nevertheless, as the collection above also illustrates, no consensus seems to exist regarding the colors to be used for communicating this message.

Studies from several countries present research covering many aspects regarding pictogram variants for this referent:

Collins & Pierman (1979) included a pictogram displaying a white telephone handset on a red background, labeled as Collins and marked with *) above, in a case study regarding fire safety symbols. In a Comprehension Test with a sample of 143 respondents 65 % of the answers could be classified as correct for this variant. In follow-up research examining the effects of variations in both presentation and response methods upon the measurement of understandability of symbols (Lerner & Collins, 1980), the subjects were told that the variants tested are fire-safety symbols. Regarding the different testing and scoring conditions, percentage of correct answers reported for that pictogram was between 71.1 and 93.5.

In Appropriateness Ranking Tests conducted in Austria (Brugger, 1984) and Sweden (Gärling, 1985) a total of seven variants, labeled 1) to 7) above, were studied. In both countries the pictogram displaying a telephone handset with the letters SOS and marked as 1) was generally preferred to all other variants, and the telephone handset in outline with an exclamation mark on the right, marked as 7), was judged as least comprehensible. The numbering 1) to 7) reflects the final rank order after merging results from both studies.

In the following ISO comprehension test series, conducted in Australia, Austria, Hungary, Japan, and the United Kingdom (Brugger 1987), the three pictograms marked with 1), 2) and 5) above were examined. The variants displaying additional elements in combination with the letters SOS were understood better than the three letters SOS alone as presented in the testdesign marked with 5), which performed less well especially in Japan. Pictogram 1) reached 79.8 % correct, compared to 58.8 % for the variant with SOS only.

Data regarding safety signs available from the Eco-Mo Foundation (2001) is based on a multiple choice format with only four possible choices. Under such conditions - even if the symbol used is far from perfect - results with correct responses close to 100 % are to be expected in case distractors used are not flawless or reasonable enough. The pictogram labeled Eco-Mo Foundation reached a score 93.2 in that study. In later research among Hong Kong Chinese students the image of a white telephone handset on green background marked with +) was examined also using a multiple choice question with four options. The fact that only 67.84 % of the highly educated respondents selected the correct answer (Ng et.al., 2011) illustrates that the concept of relying just on color coding is insufficient to convey the intended message.

Recommendations

EmergencyCall

Based on data available, we recommend the use of a pictogram like public information symbol No 114: Emergency Call from ÖNORM A 3011 part 6. To provide maximum visibility and readability, especially for persons with impaired vision, the letters S in SOS should be optimized like the letter S in the Tern regular typeface, to avoid confusions with the numbers five and eight.

Tests of pictograms of referent Emergency Call and Emergency Telephone

Brugger, Ch. (1984): Reihungstest 1984. Report to the Austrian Standards Institute (ON) dated 19/84, Vienna.

Brugger, Ch. (1987): Evaluation of Public Information Symbols, ISO 1986 Test Series: Comprehension/Recognition Test. Vienna: ISO / TC 145 / SC 1.

Collins, B.L. & Pierman, B.C. (1979): Evaluation of Safety Symbols. Washington, D.C.: National Bureau of Standards, NBSIR 79-1760, June 1979.

Eco-Mo Foundation (2001): Test data of public information symbols in Japan - Procedure for the testing of public information symbols by the Study Committee. ISO: ISO/TC 145/SC 1 N 329.

Gärling, T. (1985): ISO Appropriateness Ranking Test 1985 - Redovisning av genomförande. Report to the Swedish Standards Institute dated 1985-07-24.

Lerner, N.D. & Collins, B.L. (1980): The Assessment of Safety Symbol Understandability By Different Testing Methods. Washington, D.C.: National Bureau of Standards, NBSIR 80-2088, August 1980.

Ng, A., Lo, H. & Chan, A. (2011): Measuring the Usability of Safety Signs: A Use of System Usability Scale (SUS). Lecture Notes in Engineering and Computer Science. 2.