A bridge is a structure built to span physical obstacles without closing the way underneath such as a body of water, valley, or road, for the purpose of providing passage over the obstacle, usually something that can be detrimental to cross otherwise.
BASIC RULES
• The number of light levels recommended depends on the height of the structure;
• The number and arrangement of light units at each level should be placed so the lighting is visible from every angle in azimuth;
• Lights are applied to display the general definition of an object or a group of buildings;
• Width and length of buildings determine the number of lights installed at the top and at each light level.
LIGHTS SPECIFICATIONS
Low intensity lights should be used for structure with H ≤ 45 m during night time, if those are considered inadequate, than medium - high intensity lights should be used.
Medium intensity lights type A,B or C should be used to lit extensive object (group of buildings or tree) or structure with 45 m < H ≤ 150 m.
Note: Medium intensity lights, type A and C should be used alone, whereas medium intensity lights, Type B should be used either alone or in combination with LIOL-B.
High intensity type A, should be used to indicate the presence of an object if its H > 150 m and an aeronautical study indicates such lights to be essential for the recognition of the object by day.