In the UK Highway Code for England, Scotland and Northern Ireland, a built-up area is a settled area in which the speed limit of a road is automatically 30 mph (48 km/h). In Wales it's 20 mph (32 km/h). These roads are known as 'restricted roads' and are identified by the presence of street lights.
In 1930, the concept of specific regulation for roads within built-up areas appears. It defines the road as a road within built-up area if some system of street lighting exists at less than 200 yards (183 meters) from that road, unless decided other way by the local authority and written on traffic signs.[1]
The Road Traffic Regulation Act 1984 is the basis of the current law.
In 2018, mainland UK became a member of the Vienna convention on road traffic which consider that the concept of built-up area should be defined by the domestic legislation.
In August 2006, the Department for Transport issued new guidance relating to speed limits. It states that:[2]
Section 82(1)(a) (of the Road Traffic Regulation Act 1984 (RTRA 1984)) defines a restricted road in England and Wales as a road which is provided with "a system of street lighting furnished by means of lamps placed not more than 200 yards apart". Section 81 specifically makes it an offence for a person to drive a motor vehicle at a speed of more than 30 mph on a restricted road.
"Street lighting" is further defined as follows:[citation needed]
As set out in paragraph 45, it is generally recognised that a 'system' of street lighting could be three or more lamps spaced not more than 183 metres apart. However, street lighting (for the purposes of determining whether or not a road is a restricted) is not necessarily limited to street lamps, but may extend to lighting provided by authorities or parish councils.
To avoid confusion that could arise if some 30 mph zones were 'street-lit' and some were not, DfT guidance goes onto say:[citation needed]
Direction 11 of The Traffic Signs Regulations and General Directions 2002 (TSRGD 2002) defines the requirements for the placing of speed-limit repeater signs. This states that speed-limit repeater signs cannot be placed along a road on which there is carriageway lighting not more than 183 metres apart and which is subject to a 30 mph speed limit. The Department will not make exceptions to this rule.
This has led to the conclusion that:[citation needed]
This means it should be assumed that, unless an order has been made and the road is signed to the contrary, a 30 mph speed limit applies where there are three or more lamps throwing light on the carriageway and placed not more than 183 metres apart.
British Standards on "Road Lighting" are contained in the following documents: BS EN13201-1-2004; BS 5489:1:2003[3]
Most road traffic law pertaining to speed limits is contained in the Road Traffic Regulation Act 1984 (RTRA 1984). Other relevant legislation includes the Highways Act 1980, where Sections 90A-F cover road humps and Sections 90G-I cover other traffic-calming works. Part VI of the RTRA 1984 deals specifically with speed limits, with Sections 81–84 dealing with different speed limits and the speed-limit order-making process.
In Northern Ireland, the Highway Code of Northern Ireland has only three references to the "built-up area" and does not define it.
In Northern Ireland, the Highway Code forbids the use of the horn within built-up area between 2330 and 0700, except in case of danger,[4] consistently with article 28 of the Vienna convention.[5]
In Northern Ireland, the Highway Code forbids speeds higher than 30 mph in built-up areas.[4]