Stop sign
The finalized version by the United Nations Economic and Social Council's Conference on Road Traffic in 1968 (and in force in 1978) proposed standard stop sign diameters of 600, 900 or 1200 mm (24, 36 or 48 inches).
Some modern stop signs have flashing LEDs around the perimeter, which has been shown to substantially reduce crashes.
[8] The first stop sign was created in 1914[9] by Detroit police sergeant Harold "Harry" Jackson, who was working as a traffic guard at a busy city intersection.
Looking for ways to make his job easier, he took a rectangular piece of plywood, cut off the corners to give it a distinct shape, wrote "STOP" over the center and placed facing the street.
[citation needed] The more urban-oriented National Conference on Street and Highway Safety (NCSHS) advocated a smaller red-on-yellow stop sign.
[16] The 1954 MUTCD newly specified a white stop legend on a red field, and increased the mount height specification to 5 feet in rural areas.
The Convention specifies that stop be written in English or the national language, and also allows a circular sign with red legend.
In Spanish and Portuguese-speaking Caribbean and South American countries (Argentina, Bolivia, Brazil, Chile, Colombia, Cuba, Dominican Republic, Ecuador, Paraguay, Peru, Puerto Rico, Uruguay, and Venezuela), signs bear the legend pare ("stop" in Portuguese and Spanish).
Newly installed signs thus use only one word, more commonly only arrêt in Québec, while stop is seen in predominantly English-speaking areas.
[24] Bilingual signs with stop arrêt are still placed in areas of Alberta, New Brunswick and Manitoba; the Acadian regions of Nova Scotia, and Prince Edward Island; on federal property in the National Capital Region; and at all border crossings of the Canada–United States border.
[citation needed] On First Nations or Inuit territories, stop signs sometimes use the local aboriginal language in addition or instead of English, French, or both, such as Inuktitut notkagit.
North America and South Africa use all-way stops in some intersections unlike in some countries where they are legally prohibited.
[27] In a majority[citation needed] of Central Asian countries, as well as Cuba in North America, junctions without traffic lights or roundabouts are controlled by stop signs on minor roads and by white, yellow and black priority diamond signs on the major road.
In the United States, the stop sign is not intended as a traffic calming device,[6] but is meant to be installed mainly for safety or to assign right-of-way.
[28][29] Other research has concluded that multiway stop signs do not effectively control traffic speeds, and can give rise to negative effects including increased traffic noise and pollution from braking and accelerating vehicles, enforcement problems, and reduced sign compliance.
The sign normally stows flat on the left side of the bus, and is deployed by the driver when opening the door for picking up or dropping off passengers.
[citation needed] In Europe, stop signs are generally placed at sites where visibility is severely restricted, or where a high crash rate has been noted.
In the United Kingdom, stop signs may only be placed at junctions with tramways or sites with severely restricted visibility.
Section 79 of the Highways Act 1980 enables the government to improve visibility at junctions, as by removing or shortening walls or hedges.
[33] The former UK practice of using "Halt" or "Slow" at Major Road Ahead signs was discontinued in 1965 at the recommendation of the Worboys Committee.
The automobile manufacturer Tesla removed a "rolling stop" feature from its self-driving software after the National Highway Traffic Safety Administration complained the practice is unsafe and illegal everywhere in the United States.
[45] Since 2017, more states have implemented changes to the law similar to Idaho's: Delaware (2017),[46] Oregon (2020), Washington (2020), Utah (2021) and North Dakota (2021).
Cyclist advocacy groups have sought similar "Idaho stop" laws for other jurisdictions in the United States.
A better solution is to randomly remove one stop sign from all directions, which could lead to significant efficiency gains while ensuring safe traffic.
