Gantry (road sign)
|This article needs additional citations for verification. (December 2007)|
- For other uses see Gantry (disambiguation).
A gantry (also known as a sign holder, road sign holder, sign structure or road sign structure) is a traffic sign assembly in which signs are mounted on an overhead support, or railway signals supported.
Gantries are usually built on high-traffic roads or routes with several lanes, where signs posted on the side of the highway would be hard for drivers to see. Gantries may be cantilevered or one sided on the left, right and center (sometimes referred to as a half-gantry or Butterfly gantry), or they may be bridges with poles on each side. Similar gantries are used in railway signalling on multi-track lines.
Around the world
Gantry signs are commonly used in urban highways in Canada to support overhead signs. Half-gantries are used to place signs near exits where space does not permit to have signs to the right side of the roadway. Gantries can also be used to hold cameras for toll road entrances/exits and to hold electronic information signs. The style of gantry used are mostly truss gantries. Older gantries have truss supports (round or box) and newer ones are now supported by cylindrical legs.
Hong Kong's highways use a Gantry crane type to support signs. The road signs are usually located on top and some have lights to indicate open or closed lanes.
Gantry signs are being installed at various locations around the trunk motorway network as increasing amounts of traffic mean that road signs at the side of the carriageway are constantly being obscured by large goods vehicles. They may also consist of variable-message signs, and more recently Active Traffic Management, to close lanes due to accidents etc. They can also be used to specify temporary speed limits. Gantries in the United Kingdom display exit (junction) numbers, distances to junctions / exits (1 mile, 1/2 mile, 1/4 mile, 1/3 mile, 3/4 mile, 2/3 mile) and destinations reached, and if necessary what lane to use for them.
Gantry signs are used frequently in the U.S., particularly in urban areas where freeways have an exit every mile to fit in with the grid system. These half-gantries usually have the exit number and the road or street that can be reached. Gantries can also span the whole carriageway, such as at major junctions.
- W, M and N's
- Pedestal - for free and toll roads
- Tubular pipes
- At-grade intersection
- Controlled-access highway
- Limited-access road
- Toll road
- Traffic sign
- Variable-message sign
- Media related to Road sign gantries at Wikimedia Commons