A stop sign is a traffic sign, usually erected at road junctions, that instructs drivers to stop and then to proceed only if the way ahead is clear.
Standard stop signs have a specified size of 75 cm (30 in) across opposite flats of the red octagonal field, with a 20 mm (¾ in) white border. The white uppercase letters forming the "STOP" legend are 25 cm (10 in) tall. . Larger signs of 90 cm (36 in) with 30 cm (12 in) legend and 25 mm (⅞ in) border are used on multilane expressways. Regulatory provisions exist for extra-large 120 cm (48 in) signs with 40 cm (16 in) legend and 30 mm (1¼ in) border for use where sign visibility or reaction distance are limited, and the smallest permissible stop sign size for general usage is 60 cm (24 in) with a 20 cm (8 in) legend and 15 mm (⅝ in) border.. The metric
units specified in the US regulatory manuals are rounded approximations
units, not exact conversions. Field, legend, and border are all retroreflective
The stop sign is specified with the English legend "STOP" in the UN Convention on Road Signs and Signals. It is one of few such signs also used in the United States. This is because the sign's distinctive design was developed and first used in the US, and later adopted by other countries and the UN.
In the US, South Africa and Canada, stop signs may be augmented
with additional information by means of a supplementary plaque
bearing a legend such as "ALL WAY" or "4 WAY", mounted immediately below the bottom edge of the octagonal stop sign. In the past, this kind of supplemental information was presented by white legend text on the stop sign itself, above and smaller than the primary "STOP" legend, but such an arrangement is no longer permitted. This supplemental information is to allow drivers to discern three- or four-way stops from a two-way stop at which cross traffic is not required to stop. If there is only a stop sign with no supplemental plate, the assumption has to be that cross traffic will not
stop. Supplemental plates are provided on the principle that if they are missing because of disrepair or vandalism, the message presented by the sign will indicate a situation more potentially hazardous than it actually is, rather than less.
Stop signs can also be augmented with flashing red lights mounted directly above the intersection. Such an arrangement is usually only found at four-way stop intersections, with flashing red lights facing all four directions, or at intersections with a high number of accidents.
Placement & standardization
Stop signs are found all over the world. In Europe they tend to be used far more sparingly than in North America. Most European intersections lacking traffic lights are controlled by give way signs
or equivalent road markings, or are replaced by (mini) roundabouts
. Stop signs are generally restricted (on the principle that familiarity breeds contempt) to situations wherein coming to a dead stop is absolutely essential because of poor visibility.
Stop signs are often used in North America to control conflicting traffic movements at dangerous intersections which are not busy enough to justify the installation of either traffic lights
or, especially in Europe, a roundabout
. In the United States, the stop sign is not intended for use as a traffic calming
device.; they are meant to be installed mainly for safety and/or to assign right-of-way for a certain direction. Nevertheless, in the United States
, they are commonly used as a safety measure in residential areas and near places where children play or frequent accidents make extra precautions necessary, and it is not uncommon for stop signs to be erected on all three or four intersecting roads, known as three
or four-way stops
On school buses
A standard stop sign equipped with one round red light above and one below the "STOP" legend is required equipment on North American school buses
. The sign is placed on the left side of the bus, and the lights blink alternately to warn drivers against illegally passing the bus while it is stopped to admit or discharge passengers. When not in use, the sign folds flat against the side of the bus. Some buses have two such signs, one near the front and one near the rear.
Within the United Kingdom, stop signs may be erected only at sites approved in writing by the Secretary of State, and Highway Authorities wishing to erect a Stop sign should make an application via the Director (Transport). Current UK technical guidance states that before an application for the approval of a stop sign is made, the possibility of making a visibility improvement at the junction should always be investigated. If improvements are not considered possible, the Highway Authority should give information and explain the reasons why an improvement cannot be provided when making its application. Restriction of visibility by a wall or hedge which can be reduced in height or removed will not normally justify a stop sign.
Section 79 of the Highways Act 1980 grants powers to Highway Authorities enabling them to improve visibility at junctions.
Laws and regulations regarding how drivers must comply with a stop sign vary by jurisdiction. In the United States and Canada, these rules are set and enforced at the state or provincial level. At a junction where two or more traffic directions are controlled by stop signs, generally the driver who arrives and stops first continues first. If two drivers in different directions stop simultaneously at a junction controlled by stop signs, generally the driver on the left has to yield.
In all countries, the driver must come to a complete stop at a stop sign, even if no other vehicle or pedestrian is visible. However, some drivers practice an illegal maneuver called a rolling stop or nicknamed after a city or region regarded as somewhere it is commonplace (e.g. "California stop") - slowing down significantly but not stopping completely at the sign. The maneuver often involves pausing the car just long enough to stop moving forward, but not long enough for the body of the car to rock back completely, which would make it a full stop. This "stop" is not acceptable to most law enforcement officials.
Vandalism & modification
The intentional removal of stop signs began in the 1980s as a college
prank and, today, one may find illegally obtained stop signs hanging in the occasional college dorm
room. The intentional removal of stop signs from their posted locations is a crime in the U.S.
Moreover, a fatal accident caused by someone removing a stop sign on purpose could result in manslaughter
charges against the offender.
Stop signs are often vandalized in protest-related ways. For example, vegetarian and anti-car activists sometimes affix "eating meat" or "driving" decals below a stop sign's legend, creating a "STOP eating meat" or "STOP driving" message. During the Bush presidency era, the words "War" and "Bush" have been spray-painted on stop signs, thus presenting "Stop Bush" or "Stop War".
Stop signs originated in Michigan
in 1915. The first ones had black letters on a white background and were somewhat smaller than the current sign. As stop signs became more widespread, a committee supported by the American Association of State Highway Officials
(AASHO) met in 1922 to standardize them, and selected the octagonal shape that has been used in the United States ever since. The unique eight-sided shape of the sign allows drivers facing the back of the sign to identify that oncoming drivers have a stop sign and prevent confusion with other traffic signs. It was also chosen so that it could be identified easily at night, since the original signs were not reflective. The National Conference on Street and Highway Safety (NCSHS), a group competing with AASHTO, advocated a smaller red-on-yellow stop sign. These two organizations eventually merged to form the Joint Committee on Uniform Traffic Control Devices, which in 1935 published the first Manual on Uniform Traffic Control Devices
for Streets and Highways (MUTCD) detailing the stop sign's specifications.
The MUTCD stop sign specifications were altered eight times between 1935 and 1971, mostly dealing with its reflectorization and its mounting height. From 1924 to 1954, stop signs were made with a black "STOP legend on a yellow field. In 1954, the sign gained its current white legend/red field color configuration. Red signifies stop on traffic signals, so this specification unified red as a stop signal whether indicated by sign or by light. The mounting height reached its current level of in 1971; previously, stop signs were typically mounted two or three feet above the ground.
The already-widespread use of the MUTCD stop sign became law in the United States in 1966. In 1968 this sign was adopted by the Vienna Convention on Road Signs and Signals as part of United Nations Economic Commission for Europe's effort to standardize road travel across borders. The Convention specifies that 'stop' be written in English or the national language and allows an alternative circular yellow sign. Many European countries are party to the Convention. English speaking countries, the exception being India, are not party to the Convention but usually use the red octagonal stop sign per their own standards, like the MUTCD. Even in countries not associated with either standard mentioned above the red octagonal stop sign is often used. Unique types of stop signs may be still be observed in countries like Japan.
Although all English-speaking and European countries use the English legend "STOP" on stop signs, some jurisdictions use a roughly equivalent word in their primary language instead or in addition; its white legend/red field appearance is otherwise the same. The few known exceptions include Israel, where a solid white octagon on a red octagonal field is used, Japan which uses the local word for Stop
in white type on an inverted solid red triangle, and Zimbabwe which uses a disc bearing a black cross and the word STOP
. In Russia
and also some other countries with a Cyrillic alphabet, the legend sometimes still is in Cyrillic
: "СТОП", sometimes accompanied by "STOP" in Latin alphabet.