On 8 November 1968, at Vienna, the Convention on Road Signs and Signals was concluded, at the United Nations Conference on Road Traffic (7 October–8 November). Five equally authentic texts: Chinese, English, French, Russian and Spanish. Depositary: the Secretary-General. It is not the Vienna Convention on Road Traffic, opened the same day, and not the Geneva Protocol of 1949.

The preamble: international uniformity of road signs, signals, symbols and road markings is necessary in order to facilitate international road traffic and to increase road safety. Article 2: Annexes 1–9 (danger warning, priority, level-crossings, regulatory signs, informative signs, standing and parking, additional panels, road markings, colour reproductions) are integral parts of the Convention. Article 5: three classes — danger warning; regulatory (priority, prohibitory or restrictive, mandatory); informative (advance, direction, road identification, place identification, confirmatory and other information). Where a choice of signs exists, Parties adopt only one throughout their territories and endeavour to reach regional agreements.

Article 3: the Parties accept the system and undertake to adopt it as soon as possible. Where the Convention prescribes a sign for a rule, they shall not use another; where it does not, they may use their own signs provided they are compatible. Temporary experimental derogations on certain sections of road are allowed. Not later than four years from entry into force in their territories they shall replace signs which have the characteristics of the system but a different meaning; within fifteen years, those which do not conform, previous signs being retainable beside the new ones during familiarisation. They are not required to adopt every type; they shall limit the number to what is strictly necessary. Article 4: nothing unrelated to the purpose of a sign may be affixed to it or its support; no device which might be confused with signs, reduce their visibility or dazzle or distract road-users.

Later chapters describe placement, light signals for vehicles and pedestrians, road markings (a continuous line shall not be crossed; a broken line guides or warns; paint yellow or white, blue for parking places) and road works. Article 37: open for signature at United Nations Headquarters, New York, until 31 December 1969 for Members of the United Nations, of the specialized agencies, of the IAEA, Parties to the ICJ Statute, and invited States. Article 39: entry into force twelve months after the fifteenth instrument. The United Nations Treaty Series records 6 June 1978, No. 16743, volume 1091, p. 3.

Article 40: upon entry into force the Convention terminates and replaces, in relations between the Contracting Parties, the Convention concerning the Unification of Road Signals opened at Geneva on 30 March 1931 or the Protocol on Road Signs and Signals opened at Geneva on 19 September 1949. Later amendments are not treated here, and current party counts are not given.

Neue Burg, Hofburg, Vienna. A conference palace in the city, not the confirmed signing hall. Wikimedia Commons, CC BY-SA 4.0.

For context: Vienna Convention on Road Signs and Signals. The text: UNTS vol. 1091, p. 3, No. 16743.