Speed limits on road traffic, as used in most countries, set the legal maximum speed at which vehicles may travel on a given stretch of road. Speed limits are generally indicated on a traffic sign reflecting the maximum permitted speed, expressed as kilometres per hour (km/h) or miles per hour (mph) or both. Speed limits are commonly set by the legislative bodies of national or provincial governments and enforced by national or regional police and judicial authorities. Speed limits may also be variable, or in some places nonexistent, such as on most of the Autobahnen in Germany.
Traffic signs or road signs are signs erected at the side of or above roads to give instructions or provide information to road users. The earliest signs were simple wooden or stone milestones. Later, signs with directional arms were introduced, for example the fingerposts in the United Kingdom and their wooden counterparts in Saxony.
Prohibitory traffic signs are used to prohibit certain types of manoeuvres or some types of traffic.
A dual carriageway (BrE) or a divided highway (AmE) is a class of highway with carriageways for traffic travelling in opposite directions separated by a central reservation (BrE) or median (AmE). Roads with two or more carriageways which are designed to higher standards with controlled access are generally classed as motorways, freeways, etc., rather than dual carriageways.
The road hierarchy categorizes roads according to their functions and capacities. While sources differ on the exact nomenclature, the basic hierarchy comprises freeways, arterials, collectors, and local roads. Generally, the functional hierarchy can more or less correspond to the hierarchy of roads by their owner or administrator.
A limited-access road, known by various terms worldwide, including limited-access highway, dual-carriageway, expressway, and partial controlled-access highway, is a highway or arterial road for high-speed traffic which has many or most characteristics of a controlled-access highway, including limited or no access to adjacent property, some degree of separation of opposing traffic flow, use of grade separated interchanges to some extent, prohibition of slow modes of transport, such as bicycles, horse-drawn vehicles or ridden horses, or self-propelled agricultural machines; and very few or no intersecting cross-streets or level crossings. The degree of isolation from local traffic allowed varies between countries and regions. The precise definition of these terms varies by jurisdiction.
A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway, motorway, and expressway. Other similar terms include throughway or thruway and parkway. Some of these may be limited-access highways, although this term can also refer to a class of highways with somewhat less isolation from other traffic.
Road signs in the United Kingdom and in its associated Crown dependencies and overseas territories conform broadly to European design norms, though a number of signs are unique: direction signs omit European route numbers, and road signs generally use the imperial system of units, unlike the rest of Europe. Signs in Wales and parts of Scotland are bilingual.
Road signs in Norway are regulated by the Norwegian Public Roads Administration, Statens vegvesen in conformity with the 1968 Vienna Convention on Road Signs and Signals, to which Norway is a signatory.
An advisory speed limit is a speed recommendation by a governing body, used when it may be non-obvious to the driver that the safe speed is below the legal speed. It is a posting which either approximates the Basic Speed Law or rule or is based on a maximum g-force exerted at a specific speed. Advisory speed limits are often set in areas with many pedestrians, such as in city centres and outside schools, and on difficult stretches of roads, such as on tight corners or through roadworks. While travelling above the advisory speed limit is not illegal per se, it may be negligence per se and liability for any collisions that occur as a result of traveling above the limit can be placed partially or entirely on the person exceeding the advisory speed limit.
European traffic signs present relevant differences between countries despite an apparent uniformity and standardisation. Most European countries refer to the 1968 Vienna Convention on Road Signs and Signals. The convention has been adopted by the following countries : Albania, Armenia, Austria, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Georgia, Germany, Greece, Hungary, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Moldova, Montenegro, Netherlands, North Macedonia, Norway, Poland, Portugal, Romania, Russia, San Marino, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey, Ukraine and the United Kingdom. The convention has not been adopted by Ireland, Iceland or Malta.
Road signs in Italy conform to the general pattern of those used in most other European countries, with the notable exception that the background of motorway (autostrada) signs is green and those for 'normal' roads is blue. They are regulated by the Codice della Strada and by the Regolamento di Attuazione del Codice della Strada in conformity with the 1968 Vienna Convention on Road Signs and Signals.
Road signs in Thailand are standardized road signs similar to those used in other nations but much of it resembles road signage systems used in South American countries with certain differences, such as using a blue circle instead of a red-bordered white circle to indicate mandatory actions. Until the early 1980s, Thailand closely followed American, European, Australian, and Japanese practices in road sign design, with diamond-shaped warning signs and circular restrictive signs to regulate traffic. The Department of Railway maintains a standard on the typeface used in the sign, with custom made type for Thai text, unofficially named “Thang Luang”(อักษรทางหลวง) and a small derivation of FHWA Series fonts typeface, which is used on American road signage, for Latin text. In most Bangkok Metropolitan Area's routes, TS Lopburi is still used.
Road speed limits in the United Kingdom are used to define the maximum legal speed for vehicles using public roads in the UK.
Road signs in New Zealand are similar to those set by the Vienna Convention on Road Signs and Signals. While New Zealand is not a signatory to the convention, its road signs are generally close in shape and function. New Zealand uses yellow diamond-shaped signs for warnings in common with Australia, the Americas, Ireland, Japan and Thailand. Speed limit signs are a red circle with a white background and the limitation in black, and are in kilometres per hour. There are also some signs unique to New Zealand. Road signs in New Zealand are controlled by NZ Transport Agency Waka Kotahi and are prescribed in the Land Transport Rule: Traffic Control Devices 2004 and set out in the Traffic Control Devices (TCD) Manual.
Road signs in Switzerland and Liechtenstein generally conform to the 1968 Vienna Convention on Road Signs and Signals.
Road signs in Australia are regulated by each state's government, but are standardised overall throughout the country. In 1999, the National Transport Commission, or NTC, created the first set of Rules of the Road for Australia. Official road signs by standard must use the AS1744 series fonts, based on the US' Highway Gothic typeface.
Road signs in Armenia are similar to the signs of other post-Soviet states and most European road sign systems. Armenia is a signatory of the Vienna Convention on Road Traffic and the Vienna Convention on Road Signs and Signals. The Ministry of Transport regulates these icons, while the police enforces them. Road signs ensure transport vehicles move safely and orderly, as well as, to inform both pedestrians and motorists of traffic rules.
The road signs, used on the Serbian road network, are regulated by the "Regulation of Traffic Signs", which was last time modified in 2017.
Road signs in the Republic of Bulgaria were introduced by the Road Traffic Act and are regulated by:
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