Chapter 6: Lighting Design and Layout

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Section 1: Overview

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Project Design Procedures

Highway illumination project designers generally follow the steps shown in the following table.

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Determine whether the lighting will be safety lighting or continuous lighting; then check to see to what extent lighting is warranted. (See Chapter 2.)

If the project is inside a city’s limits, contact the city to see if they are willing to help finance continuous lighting for the project. (See Chapter 4.) Obtain the proper lighting agreement.

Determine what type of lighting to use (pole height, median or house side mounting or high mast). (See guidelines and standards throughout this chapter.)

Place lighting poles for the entire project. (See Spacing of Light Poles and Pole Placement Guidelines of this chapter.)

Contact utility company to determine the type of service available and possible electrical service locations. (See Chapter 7, Electrical Service. )

Lay out circuits, keeping road crossings to a minimum, as jacking or boring escalates costs. (See Chapter 7, Circuit Design. )

Determine and label poles, length and size of wire, conduit, and duct cable.

NOTE: Show pole station number and offset from base line or edge line if applicable.

For poles with similar offsets, offset can be shown by plan note.

For poles with similar offsets, offset can be shown by plan note.

Electrical service numbers and light pole numbers are recommended.

Electrical service numbers and light pole numbers are recommended.

Prepare sheet summaries and project summaries. (The project summary shows the items and quantities needed for the entire project. It is compiled from the sheet summaries and usually includes the electrical service data.)

If the project is inside a city limit, submit plans and title sheet with the proper quotation for city approval and signature. (For example, see Chapter 4, Quotation on Plan Title Sheet. )

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Project Lead Time

For projects involving mainly illumination, an appropriate lead time must be allowed for the contractor to obtain the necessary materials. Typical lead time is 90 days for conventional lighting and 120 days for high mast lighting. This gives the pole manufacturers ample time to get shop drawings approved and poles constructed.

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Joint Usage Encouraged

Joint usage of poles is encouraged to reduce roadside clutter and the number of fixed objects along the roadside. When lighting is provided at signalized intersections and when conditions permit, the luminaries should be mounted on the traffic signal pole.

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Luminaires on Traffic Signal Poles

Luminaires on traffic signal poles should be powered from the same electrical service that powers the traffic signal.

Luminaire arms should be perpendicular to the roadway to be lighted.

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Circuits Crossing Bridges

For circuits crossing bridge structures, use NEC type XHHW conductor in rigid metal conduit and show a junction box for grounding the metal conduit.

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Railroad Crossings

For work involving railroad overpasses, consult the Railroad Operations Manual (Traffic Operations Collection) for required agreements with or notification of railroad companies.

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