authority, its coat of arms, or part of the street’s postcode. Location identifiers Numbered location markers of one type or another are used to identify specific locations along a road. Historically, milestones were used, but since the early 20th century they fell into disuse. However, for administrative and maintenance purposes, distance marker posts and driver location signs have been erected on motorways and certain dual carriageways. The numbers on distance marker posts are embedded into emergency roadside telephone numbers and are used by the emergency services to pinpoint incidents. The advent of the mobile phone meant that drivers were not accessing location information embedded into motorway emergency telephone systems, and since 2007 driver location signs have been erected on many motorways. These contain important information about the location and carriageway direction. Traffic lights Icon Obsolete Post-Worboys Pre-Worboys Northern Ireland The designs of road signs in Great Britain as prescribed in the Traffic Signs Regulations and General Directions (TSRGD) apply specifically to England, Scotland and Wales. These regulations do not extend to Northern Ireland. Traffic signs in Northern Ireland are prescribed by The Traffic Signs Regulations (Northern Ireland) 1997 and are administered by the Northern Ireland Assembly. Northern Ireland signs are broadly the same as those in Great Britain, although changes made in Great Britain are often not made in Northern Ireland at the same time. One example is the series of bends ahead sign, which was removed from TSRGD in 1975 but only removed from the Northern Ireland regulations in 1979. Crown dependencies The designs of road signs as prescribed in the Traffic Signs Regulations and General Directions (TSRGD) do not extend to other territories that come under the jurisdiction of the Crown. Road signs in the Channel Islands and the Isle of Man are under the jurisdiction of their local legislatures. Although the policy in these territories is to align their road signs with those prescribed in the TSRGD, small variations may be seen. Isle of Man The Tynwald (Isle of Man Parliament), through its Traffic Signs (Application) Regulations 2003, explicitly included Part I of the TSRGD into Manx law, but not the other parts of that legislation. One of the consequences of this partial incorporation is that while in England and Wales speed limit signs had to appear on both sides of a carriageway until 2016, this was not necessary for the Isle of Man. Likewise, an all-way