used - In the eastern suburbs of Melbourne Chadstone & Dandenong, which are connecting hubs with the national route 1, Princes Highway, are used as route markers. Traveling inbound, depending upon the driver's location in Melbourne's east one of these markers will generally be used along with a marker 'City' referring to the Central Business District. The marker 'City' is only used when within the metropolitan area of a city, outside of the metropolitan area routes traveling towards that city will use the city's full name. Outside of cities, major regional centers or capital cities will generally be used as markers. The same principle applies to major and secondary surface roads in Australia, with the most major suburb or town, or the road's terminus in either direction being used as the 'control city'. On the main routes connecting Australia's major cities, the next interstate capital is often used signposted in addition to the next regional centre. The Northern Queensland town of Cairns has a similar status. In some circumstances a major infrastructure location, most often Airports, will be used as a 'Control' City. In the case of surface roads if they connect to a freeway, motorway or tollway sometimes this connection will be used as a signing point. Guidelines to control city selection There is no absolute threshold of community size or distance away, or absolute necessity that it has to be a city per se in order to be selected. Even some highways will terminate several miles before the so-called "control city" and "borrow" another route to continue toward there, even if a north–south highway has to externalize its control city to an east–west highway. For instance, Interstate 75 in Michigan uses the Mackinac Bridge as a "control city", and even U.S. Route 127 in Michigan does it as far south as Mt. Pleasant. Another idiosyncrasy with control cities is there is no absolute rule that the city has to be reached before the control city changes, for instance Interstate 94 in Michigan uses Chicago as a control city as far as the Metro Detroit area, whereas some in-between cities such as Jackson are used within of there. Other control cities are used where a city can be several miles east of a north-south route, such as U.S. Route 35 using Charleston, West Virginia, as a control city even though the southern junction is at Scott Depot, West Virginia,