Highway Illumination Manual: Continuous Lighting 1

Section 2: Continuous Lighting

Description

A continuous lighting system provides relatively uniform lighting on main lanes, direct connections, ramp terminals, and complete interchange lighting of all interchanges. Frontage roads are not normally continuously lighted by TxDOT.

The lighting assemblies may be luminaires on conventional poles, high mast assemblies, or a combination.

NOTE: Continuous lighting requires the financial participation of the local government (see “Lighting Agreements,” Chapter 4).

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Eligibility

The following roadways are eligible for continuous lighting systems:

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urban freeways that are multi-lane divided facilities for which full control of access is provided

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multi-lane arterial highways with partial control of access where the following conditions exist:
- access is provided to abutting property
- at-grade crossings are provided at minor streets and roads, and
- grade separation structures are provided at major crossings of arterial highways, streets, and roads.

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Warrants

Continuous freeway lighting may be warranted by at least one of the conditions described in the following table.

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Case	Warranting Conditions
CL‑1	Sections in and near cities where the current average daily traffic (ADT) is 30,000 or greater.
CL‑2	Sections where three or more successive interchanges are located with an average spacing of 1.5 miles or less and adjacent areas outside the right-of-way are substantially urban in character.
CL‑3	Sections of 2 miles or more passing through a substantially developed suburban or urban area in which one or more of the following conditions exist: Local traffic operates on a complete street grid having some form of street lighting, parts of which are visible from the freeway The freeway passes through a series of developments such as residential, commercial, industrial and civic areas, colleges, parks, terminals, etc. that include lighted roads, streets, parking areas, yards, etc. Separate cross streets, both with and without connecting ramps, occur with an average spacing of 0.5 miles or less, some of which are lighted as part of the local street system The freeway cross section elements, such as median and borders, are substantially reduced in width below desirable sections used in relatively open country.
CL‑4	Sections where the ratio of night to day crash rates is at least 2 times the statewide average for all unlighted similar sections, and a study indicates that lighting may be expected to result in a significant reduction in the night crash rate. NOTE: Because the ratio of night to day crash rates for a given section of roadway cannot always be statistically verified, this measure must be considered as an aid to design rather than an absolute rule. Engineering judgment should be exercised when using this warrant.

For streets and highways other than freeways, AASHTO has not established continuous lighting warrants for the installation of roadway lighting that satisfy all conditions. In general, lighting may be considered for those locations where the relevant governmental agencies agree that lighting would contribute substantially to the safety, efficiency, and comfort of vehicular and pedestrian traffic.

Continuous lighting may be provided for all major arterials in urbanized areas and for locations or sections of streets and highways where a study indicates that lighting would significantly reduce the nighttime crash rate.

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Specially Funded Projects

For specially funded projects, the project authorization must describe the ownership and maintenance responsibilities for the continuous lighting.