For other uses see Gantry

Gantry

Gantry may refer to:*Gantry crane, a crane having a hoist fitted in a trolley for parallel movement*Gantry , the frame which encloses and services a rocket at its launch pad*Gantry , an overhead assembly on which highway signs are posted...

A gantry (a.k.a. sign holder or road sign holder) is a traffic sign

Traffic sign

Traffic signs or road signs are signs erected at the side of roads to provide information to road users. With traffic volumes increasing over the last eight decades, many countries have adopted pictorial signs or otherwise simplified and standardized their signs to facilitate international travel...

 assembly in which signs are mounted on an overhead support, or railway signal

Railway signal

A signal is a mechanical or electrical device erected beside a railway line to pass information relating to the state of the line ahead to train/engine drivers. The driver interprets the signal's indication and acts accordingly...

s 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 to see for drivers. 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

Railway signalling

Railway signalling is a system used to control railway traffic safely, essentially to prevent trains from colliding. Being guided by fixed rails, trains are uniquely susceptible to collision; furthermore, trains cannot stop quickly, and frequently operate at speeds that do not enable them to stop...

 on multi-track lines.

United Kingdom

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 vehicle

Large Goods Vehicle

A large goods vehicle , is the European Union term for any truck with a gross combination mass of over...

s. They may also consist of variable-message signs, and more recently Active Traffic Management

Active Traffic Management

Active traffic management , also known as managed lanes or smart lanes, is a scheme for improving traffic flow and reducing congestion on motorways. It has been implemented in several countries, including Germany, the United Kingdom, and the United States...

, to close lanes due to accidents etc. They can also be used to specify temporary speed limits. Gantries in the United Kingdom

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 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.

Canada

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.

United States

Gantry signs are used frequently in the USA, 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/street that can be reached. Gantries can also span the whole carriageway, such as at major junctions.