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.
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, (draught) 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.
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 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.
A speed limit is the limit of speed allowed by law for road vehicles, usually the maximum speed allowed. Occasionally, there is a minimum speed limit. Advisory speed limits also exist, which are recommended but not mandatory speeds. Speed limits are commonly set by the legislative bodies of national or local governments.
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 Vienna Convention on Road Signs and Signals.
Highways in Slovakia are divided into motorways and expressways.
Road signs in Greece are regulated by the Ministry of Transport and the Hellenic Traffic Police, according to the Greek Highway Code.
Road speed limits in the United Kingdom are used to define the maximum legal speed for vehicles using public roads in the UK.
Speed limits in Germany are set by the federal government. All limits are multiples of 10 km/h. There are two default speed limits: 50 km/h (31 mph) inside built-up areas and 100 km/h (62 mph) outside built-up areas. While parts of the autobahns and many other freeway-style highways have posted limits up to 130 km/h (81 mph) based on accident experience, congestion and other factors, many rural sections have no general speed limit. The Road Traffic Regulations (StVO) section on speed begins with the requirement which may be rendered in English:
Any person driving a vehicle may only drive so fast that the car is under control. Speeds must be adapted to the road, traffic, visibility and weather conditions as well as the personal skills and characteristics of the vehicle and load.
Four general speed limits apply on roads in Bosnia and Herzegovina:
Speed limits in the Czech Republic vary depending on the type of road, and whether the road is within a settlement or not. The top speed limit is 130 km/h (81 mph) for motorways outside of settlements, whereas on regular roads within a settlement the speed limit is 50 km/h (31 mph). outside of the settlement and other than motorway the speed limit is 90 km/h. Various other special restrictions are applied for certain types and weight categories of vehicle.
Speed limits in Croatia are regulated by the Road Traffic Safety Act.
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).
Norway has two general speed limits:
The general speed limits in Ukraine are as follows:
General speed limits in New Zealand are set by the New Zealand government. The speed limit in each location is indicated on a nearby traffic sign or by the presence of street lighting. The limits have been posted in kilometres per hour (km/h) since 1974. Before then, when New Zealand used imperial units, maximum speeds were displayed in miles per hour (mph). Today, limits range from 10 km/h (6.2 mph) to 110 km/h (68 mph); in urban areas the default speed limit is 50 km/h (31 mph).
Speed limits in Thailand are a set of maximum speeds applicable on any road in Thailand. For small cars that weigh less than 1,200 kg (2,646 lb), the maximum limits within the built-up area and outside are 80 km/h (50 mph) and 90 km/h (56 mph) respectively. The exception applies to motorways, in which small cars can use up to 120 km/h (75 mph). Heavier cars, buses and trailer have more restrictive limits. Despite having the general maximum speed limits, the limits may be altered by a roadside sign.
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.
