page_title: High-mast lighting
hierarchical_section_title: High-mast lighting
caption_attribution_description: English: A rare photograph showing the Highway 401 / Highway 402 interchange in its entirety in London, Ontario. Taken from the Digman Drive overpass, which was under repairs at the time this photo was taken. The overpass doesn't have a sidewalk, so the only time I could take photos safely from the overpass was when the bridge was closed to vehicular traffic. Permission was granted by the nearby construction workers.
context_page_description: High-mast lighting is a tall pole with lighting attached to the top pointing towards the ground, usually but not always used to light a highway or recreational field. It is used at sites that require lighting over a large area. The pole that the lighting is mounted on is generally at least 30 m tall, while the lighting consists of a luminaire ring surrounding the pole with one or several independent lighting fixtures mounted around it. Most units have four, six or eight lights in the ring, with three, five, ten, twelve and sixteen lights used in rarer instances. While most high-mast lights are high-pressure sodium, other types such as mercury vapor, metal halide and LED, have also been used. Some units have the lighting surrounded by a circular shield to prevent or reduce light pollution or light trespass from affecting neighbourhoods adjacent to the highway.
  Maintenance of these systems are done by lowering the luminaire ring from the mast head to the base using a winch and motor to the ground or at a height accessible by a cherry picker and located in areas to allow for easier access without disrupting traffic.
context_section_description: High-mast lighting is a tall pole with lighting attached to the top pointing towards the ground, usually but not always used to light a highway or recreational field. It is used at sites that require lighting over a large area. The pole that the lighting is mounted on is generally at least 30 m (98 ft) tall (under this height it is referred to as conventional lighting system), while the lighting consists of a luminaire ring surrounding the pole with one or several independent lighting fixtures mounted around it. Most units have four, six or eight lights in the ring, with three, five, ten, twelve and sixteen lights used in rarer instances. While most high-mast lights are high-pressure sodium, other types such as mercury vapor, metal halide and LED, have also been used. Some units have the lighting surrounded by a circular shield to prevent or reduce light pollution or light trespass from affecting neighbourhoods adjacent to the highway.
  Maintenance of these systems are done by lowering the luminaire ring from the mast head to the base using a winch and motor to the ground or at a height accessible by a cherry picker and located in areas to allow for easier access without disrupting traffic.
caption: High-mast lighting used on Ontario Highway 401 during the day
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