The Boulevard Périphérique, often called the Périph, is a limited-access dual-carriageway ring road in Paris, France. With a few exceptions, it is situated along Paris's administrative limit.
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 calming uses physical design and other measures to improve safety for motorists, car drivers, pedestrians and cyclists. It has become a tool to combat speeding and other unsafe behaviours of drivers. It aims to encourage safer, more responsible driving and potentially reduce traffic flow. Urban planners and traffic engineers have many strategies for traffic calming, including narrowed roads and speed humps. Such measures are common in Australia and Europe, but less so in North America. Traffic calming is a calque of the German word Verkehrsberuhigung – the term's first published use in English was in 1985 by Carmen Hass-Klau.
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.
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.
Standards for Interstate Highways in the United States are defined by the American Association of State Highway and Transportation Officials (AASHTO) in the publication A Policy on Design Standards: Interstate System. For a certain highway to be considered an Interstate Highway, it must meet these construction requirements or obtain a waiver from the Federal Highway Administration.
The Autobahn is the federal controlled-access highway system in Germany. The official term is Bundesautobahn, which translates as 'federal motorway'. The literal meaning of the word Bundesautobahn is 'Federal Auto(mobile) Track'.
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.
2+1 road is a specific category of three-lane road, consisting of two lanes in one direction and one lane in the other, alternating every few kilometres, and usually separated with a steel cable barrier. The second lane allows faster-moving traffic to overtake slower vehicles at regular intervals. Traditional roads of at least 10 metres (33 ft) width can be converted to 2+1 roads and reach near-motorway safety levels at a much lower cost than an actual conversion to motorway or dual carriageway.
Road speed limits in Ireland apply on all public roads in the state. These are signposted and legislated for in kilometres per hour. Speed limits are demarcated by regulatory road signs. These consist of white circular signs with a red outline. Speed limits are marked in black with "km/h" below the speed limit. Smaller "repeater" speed limit signs are used along stretches of road where there is no change in speed limit, in order to remind motorists currently on the road and to inform traffic merging from junctions that a certain speed limit applies.
Speed limits in Australia range from 5 km/h (3.1 mph) shared zones to 130 km/h (81 mph). Speed limit signage is in km/h since metrication on 1 July 1974. All speed limits, with the sole exception of the South Australian school and roadworks zones, which are signposted at 25 km/h, are multiples of 10 km/h – the last digit in all speed signs is zero. Speed limits are set by state and territory legislation albeit with co-ordination and discussion between governments.
Canadian speed limits are set by different levels of government, depending on the jurisdiction under which the road falls, resulting in differences from province to province. The limits have been posted in kilometres per hour (km/h) since September 1, 1977. Before then, when Canada used Imperial units, speed limits were in miles per hour (mph).
This article describes the highway systems available in selected countries.
French roads have a variable maximum speed limit that depends on weather conditions. In dry weather, roads in urban areas have a default speed limit of 50 km/h, and outside urban areas have the following limits:
Sweden has speed limits ranging from 30 km/h to 120 km/h, where 30, 40, 50, 60 and 70 km/h are used within towns and cities. Outside schools and hospitals the limit is often 30 km/h. 70, 80, 90 and 100 km/h are mainly used outside built-up areas where the speed limit depends on the standard and safety of the road. 90 and 100 km/h are used mainly on roads with separated lanes, however local exceptions may apply, mainly in northern Sweden, where 100 km/h (62 mph) is legal on roads with no separated lanes and where the standard of the road often is poor. The main reason for setting 100 km/h on these roads is because of their high importance to the region. Earlier it was permitted to drive 110 km/h (68 mph) on these roads but due to the poor standards the speed limit was lowered to 100 km/h in 2008.
The default speed limits in the Netherlands are 50 km/h (31 mph) inside built-up areas, 80 km/h (50 mph) outside built-up areas, 100 km/h (62 mph) on expressways (autowegen), and, as of 16 March 2020, 100 km/h from 6:00 to 19:00 and 130 km/h from 19:00 to 6:00 on motorways (autosnelwegen).
The highest speed limit in Japan is 120 km/h, which applies on sections of Shin-Tōmei Expressway (E1A) and Tōhoku Expressway (E4), and expressways in the Kantō Plain leading to Tokyo, although a speed limit of 120 km/h is planned to be introduced on some more expressways.
30 km/h zones and the similar 20 mph zones are forms of speed management used across areas of urban roads in some jurisdictions. The nominal maximum speed limits in these zones are 30 kilometres per hour (19 mph) and 20 miles per hour (32 km/h) respectively. Although these zones do have the nominal speed limit posted, speeds are generally ensured by the use of traffic calming measures, though limits with signs and lines only are increasingly used in the UK.
Speed limits in the United States vary depending on jurisdiction. Rural freeway speed limits of 70 to 80 mph are common in the Western United States, while such highways are typically posted at 65 or 70 mph in the Eastern United States. States may also set separate speed limits for trucks and night travel along with minimum speed limits. The highest speed limit in the country is 85 mph (137 km/h), which is posted on a single stretch of tollway in exurban areas outside Austin, Texas. The lowest maximum speed limit in the country is 30 miles per hour (48 km/h) in American Samoa.
Road signs in South Africa are based on the SADC-Road Traffic Sign Manual, a document designed to harmonise traffic signs in member states of the Southern Africa Development Community. Most of these signs were in the preceding South African RTSM.
