A control city is a city, locality, or other location posted on a series of traffic signs along a particular stretch of road indicating destinations on that route. Together with route numbers and cardinal directions, these focal points aid the motorist navigating along a highway system. Such cities appear on signs at junctions to indicate where the intersecting road goes and where the road ahead goes. They are also typically used on distance signs.
Different countries have different practices as far as focal points on directional signs are concerned, and the term control city is not used globally. Where a sign contains a number of destinations for a particular direction, not all of those destinations may be considered a control city. In most countries, control cities are perceived to be the destinations on signs that aid longer-distance traffic, as opposed to local traffic. Accordingly, local destinations on a sign, which only appear incidentally, would in a number of countries not be considered control cities.An example would be Germany, where the Richtlinie für die wegweisende Beschilderung auf Autobahnen distinguishes between Fernziele and Nahziele.
While a control city may not appear on the signs of every single junction, the control city would at least appear on major junctions.
Description Towns and cities are most often used as control cities. Other than major towns in a country or region, towns close to major intersections or the end of a particular route are often selected as control cities. However, a wide variety of other potential destinations can be selected as control cities, such as states or regions, frequently visited places, or names of prominent intersecting roads. Narrow corridors carrying large volumes of traffic often also take the role of control city. Examples would be major bridges (the Golden Gate Bridge is a control city within San Francisco), tunnels (e.g. the Holland Tunnel in New York City), or mountain passes (e.g. the Gotthard Pass featuring prominently on signs in Switzerland). In border areas, the border itself regularly features as a control city, e.g. the U.S.-Mexico border for Interstate 5 southbound.
The control city is typically on or close to the route for which it serves as the primary focal point. In exceptional situations, towns along prominent intersecting roads could serve as such, notably when the vast majority of traffic would turn off to that intersecting road. Equally, towns beyond a route's terminus could serve as control city. Particularly when a route merges into another route, a major town along that other route could serve as control city. In the United States, for instance, New Jersey Route 18 southbound says it goes to Point Pleasant but never does. This is because of the stub end at exit 6.
While the vast majority of control cities are sizeable towns, minor towns or even unincorporated localities may feature as control city. This is particularly the case if they are located close to junctions of major roads or near the terminus of a road. Major roads in Poland, for instance, feature many signs that refer to small villages close to the border, since that border marks the route's terminus. Signs in Australia's Northern Territory generally will not refer beyond the state border, with the last control city on the Stuart Highway being SA Border and the same applying on routes heading to Queensland and South Australia. On the other hand, there are also instances where larger cities have not been selected as control city because of the proximity of a bigger city downstream on the road.
A common principle identified in signposting is the principle of continuity. Once a particular destination has featured on a sign, it should feature on all signs that contain forward destinations for that direction. Sometimes particular towns are used on a one-off basis at major intersections, but they would then not be considered the control city for that particular road.
Europe Unlike in the United States, Canada, and the United Kingdom, roads in Continental Europe are not signed with directional banners (east, west, north, and south). The motorist accordingly needs to rely on the combination of the control city and the route number as navigation tools. Possibly as a result of this, control cities tend to feature rather prominently on the route signs of European countries when compared to signage in North America. Routes tend to feature more signs that contain information for the route forward and those signs often contain a larger number of focal points.
In this context, and bearing in mind that in Europe every country has its own style of signposting, the term control city is not always in use, but most countries use concepts that have a similar role to that of a control city in North America.
Some, but not all, countries like Poland and Switzerland label border crossings and foreign cities as control cities with the international vehicle registration code (D for Germany, NL for the Netherlands, UA for Ukraine, etc.). The border crossing control city in Poland would have priority over other towns along the way even if the signposted border village/town is smaller than many towns along the way or when the particular border crossing is no longer operational due to Poland adopting the Schengen Agreement in 2007.
Belgium In Belgium, the route network very much centers around the towns of Antwerp, Brussels, and Liège. On roads leading to these towns, the relevant town typically features as the primary focal point of the route and as the most distant focal point on the distance signs placed after each intersection. On other roads, provincial capitals play a comparable role as control city, while larger towns outside Belgium feature on routes leading out of Belgium.
France
All French localities have been divided into five categories for signposting purposes, mostly based on their size (though smaller towns with a strategic position in the road network could be promoted while larger suburban towns could be relegated one category). Towns in categories 3, 4, and 5 feature as the focal points on forward signs and distance signs of motorways. On non-motorways, these towns are signposted against a green background whereas other towns are signposted with black letters against a white background. The towns in category 5 are the biggest towns of France, which are also the pivotal points in the French motorway network.
Signs on, and leading to, French motorways generally refer to some three or four towns on that motorway. In other words, there are no stand-out towns that could be referred to as the French equivalent of a control city. The towns signposted have been picked from the three categories signposted along motorways, with towns in category 5 signposted from the biggest distance out (typically, on any motorway that leads to a town in category 5, the first category 5 town ahead is signposted).
Germany In the German guidelines for directional signage on motorways, the concept of the Hauptfernziel (translating as main distant focal point) has a role that is comparable to that of a control city in North America. This control city appears on roads leading to a motorway and at on-ramps. The Hauptfernziel is also the most distant point that features on distance signs, which are placed after each exit. Directional signage along motorways tends to also refer to towns other than the Hauptfernziel. These could be local focal points (known as Nahziele), but also smaller towns downstream.
Under German guidelines, a town close to a road's terminus should serve as Hauptfernziel, except that towns close to major functions could also take that role. The major towns of Germany typically double as Hauptfernziel on this basis, notwithstanding the fact that motorways often pass by rather than terminate there. A prominent town that does not feature as Hauptfernziel on a major route would be Düsseldorf, which despite being a regional capital sits squeezed between the major junctions at Oberhausen and Cologne and has no major motorway junction itself. On the longer motorways of Germany, the distance between Hauptfernziele is usually some , though less in densely populated areas.
Distance signs on motorways also often feature the Hauptfernziel of one or more intersecting motorways. These are separated from towns along the route proper with a horizontal line.
Ireland In the Republic of Ireland, directional banners are used on the M50 (Ó Thuaidh/NORTHBOUND and Ó Dheas/SOUTHBOUND) and on the N40 (Siar/WESTBOUND and Soir/EASTBOUND).
On national roads (which include motorways), the control city is usually a large town at or near the termination of the road. A town on an intersecting road may be used as a control city with its name enclosed in parentheses.
Italy Road signs in Italy normally feature one focal point used per direction of a longer stretch of road. This could be considered the control city of that road. Often, this is the town close to the route's terminus, but it could also be a town close to a major intersection or an otherwise major town. Milan, for instance, has this role along the A4 between Turin and Trieste.
On longer non-motorways, a provincial capital often takes the role of control city despite not being close to the route's terminus or a major intersection. Intersecting routes also feature as control city. This often occurs on beltways and spur routes.
In addition to signs showing a route's single control city, Italian routes generally also feature ancillary signs that feature other towns in a particular direction. Unlike the control city, these other towns are not necessarily to be found on subsequent signs along the route signposted. These towns feature on the directional signage for information purposes only.
Netherlands In the Netherlands, the guidelines for signposting feature a distinction between regular control cities (called hoofddoel) and network cities (called netwerkdoel). The class, a group of ten cities in each part of the country where major roads intersect, is being signposted in addition to regular control cities. The references to network control cities serve to guide long-distance traffic through the country, unlike the reference to the first regular control city which is seldom more than away. Network control cities can also be towns on an intersecting road. Since 2010, efforts are being made to create even more prominent references to the towns of Amsterdam and Rotterdam; the former drawing many tourists and the latter drawing many professional drivers to its port. On roads not leading to a network control city, the route's terminus is often signposted in addition to the control city.
Scandinavia
Each of the Scandinavian countries has its own style of signposting, but their styles reveal similarities. Signs on roads in the countries typically feature one town that takes the role of the control city of that particular road. As distances in Scandinavia are longer and the area is sparsely populated, this can be a town that is several hundred kilometers away. Other than local destinations, signs in Scandinavia do not commonly feature other cities in addition to this major town. On less important roads, the town featuring as control city is often the route's terminus. On the main axes of Scandinavia, notably the main north–south routes E4 and E6, larger towns along the routes have been chosen to also appear as control city.
United Kingdom