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Section 3: Safety Lighting

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Description

Safety lighting may be installed at any interchange, highway intersection, or other decision-making point or points of nighttime hazard. Safety lighting may be used to the extent necessary to provide for safety enhancement and the orderly movement of traffic.

There are three kinds of safety lighting: partial interchange/intersection, complete interchange/intersection, and spot. Which is used depends on the warranting conditions.

Partial interchange/intersection lighting covers:

  • acceleration and deceleration lanes
  • ramp terminals
  • crossroads at frontage road or ramp intersections
  • other areas of nighttime hazard.

Complete interchange/intersection lighting covers the limits of the interchange, including:

  • main lanes
  • direct connections
  • ramp terminals
  • frontage road or crossroad intersections.

Spot lighting is another kind of safety lighting. Spot lighting usually consists of one to five units intended to illuminate a nighttime hazard, such as sections with complex geometry or raised channelization.

For contracting purposes, all types of safety lighting are handled in the same manner.

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Eligibility

Any designated highway or marked highway route is eligible for safety lighting. All highway intersections, interchanges, points of hazard, and decision-making points where such lighting would enhance the safe and orderly movement of nighttime traffic are eligible.

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Warrants

Conditions warranting safety lighting vary depending on the type of roadway (freeway, expressway, or other designated on-system highway) and whether the proposed lighting is partial interchange, complete interchange, or spot.

Freeways and Expressways. For freeways and expressways, safety lighting may be warranted under one of the conditions described in the following table.

Anchor: #i1000008Warranting Conditions for Freeway and Expressway Safety Lighting

Type of Lighting

Case

Warranting Conditions

Partial Interchange/ Intersection

SL-1

Current average daily traffic (ADT) ramp traffic entering and leaving the freeway or expressway within the interchange area exceeds 5,000 for urban conditions or 3,000 for suburban conditions or 1,000 for rural conditions.

 

SL-2

Current ADT on the through traffic lanes exceeds 25,000 for urban con-ditions, 20,000 for suburban conditions, or 10,000 for rural conditions.

 

SL-3

Ratio of night to day crash rates within the interchange area is at least 1.25 or higher than the statewide average for all similar unlighted sections, and a study indicates that lighting may be expected to result in a significant reduction in the night crash rate. Engineering judgment should be exercised when using this warrant. See Title 43, Texas Administrative Code, Section 25.11, for additional information.

Complete Interchange/ Intersection

SL-4

Current ADT ramp traffic entering and leaving the freeway or expressway within the interchange areas exceeds 10,000 for urban conditions, 8,000 for suburban conditions, or 5,000 for rural conditions.

 

SL-5

Current ADT on the crossroad exceeds 10,000 for urban condi-tions, 8,000 for suburban conditions, or 5,000 for rural conditions.

 

SL-6

Existing substantial commercial or industrial development that is lighted during hours of darkness, is located in the immedi-ate vicinity of intersection, or where the crossroad approach legs are lighted for 0.5 miles or more on each side of the inter-section.

 

SL-7

The ratio of night to day crash rates within the interchange area is at least 1.5 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. See Title 43, Texas Administrative Code, Section 25.11, for additional information.



Other Designated On-System Highways. For other designated on-system highways, the cases described in the following table apply.

Anchor: #i1000044Warranting Conditions for Safety Lighting other than on Freeways and Expressways

Type of Lighting

Cases*

Partial Interchange/Intersection

SL-2

SL-3

Complete Interchange/Intersection

SL-5

SL-6

SL-7

*See previous table for explanation of warranting conditions.



Spot Safety Lighting. For spot safety lighting, case SL-3 applies for all types of roadways or it may be used at intersections or other areas where lighting will provide safer movement of traffic.

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Continuous Lighting Classified as Safety Lighting

A continuous lighting system may qualify as a safety lighting system, provided all of the following conditions are met:

  • the system is installed on a freeway with full control of access
  • the freeway passes through unincorporated areas or through incorporated areas with municipal populations of less than 50,000 people according to the latest federal census
  • the freeway has an average daily traffic (ADT) volume in excess of 70,000 vehicles
  • a TxDOT study of the traffic volume or nighttime crash rate of the freeway indicates that continuous lighting would substantially improve traffic safety and the efficiency of nighttime traffic.
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