Difference between revisions of "Streetlight Design Manual"
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Revision as of 16:21, 23 June 2015
General Purpose of the Design Manual:
This Streetlight Design Manual has been written to serve as a general guideline when designing a streetlighting system for the City of Overland Park, Kansas. Although there are specific design requirements, the guidelines contained herein should not be a substitute for proper engineering design and judgment based on specific project situations. The purpose of this Streetlight Design Manual is to aid consultants as well as City of Overland Park staff to be consistent in the practice of designing streetlighting plans. It provides an overview of what tasks are expected to be included in the scope of the design; what information should be included on the plan sheets; what kind of backup design information is required for proper analysis; and what is expected for the final deliverable product. Any questions regarding this manual may be directed to Bruce Wacker, P.E., Assistant City Traffic Engineer at the City of Overland Park, Kansas at (913) 895-6027 or by email at firstname.lastname@example.org.
Purpose of Streetlighting:
The principal purpose of lighting is to provide improved visibility for the street users so they can make quick, accurate and safe decisions. Street users include vehicle operators, bicycle and motorcycle operators and pedestrians. Light that falls on pedestrian walkways enhances pedestrian traffic, but the streetlighting criterion does not mandate specific lighting levels on sidewalks, bike paths or other pedestrian paths. The Planning and Development Services Department has separate criteria for the lighting of pedestrian facilities and should be consulted. This document does however, mandate specific lighting levels at the conflict points of pedestrians and vehicles, such as at intersection crossing points.
Reference to Other Documents:
Wherever applicable, this design manual should be used in conjunction with the American National Standard Practice for Roadway Lighting Illuminating Engineering Society of North America, RP-8-14, as herein modified and the National Electric Code by the National Fire Protection Association. The current editions of the City of Overland Park Streetlighting Resolution, Design and Construction Standards, Volume 1 Design Criteria (latest edition), Technical Streetlighting Construction Specifications, Standard Details and the Approved Materials List, hereafter referred to as “City Standards” should be followed during the design of any streetlighting project.
Public or Private Ownership, Operation and Maintenance:
Different policies apply to streetlighting systems based on the final ownership, operation and maintenance of the system. The two types of systems are 1) those that are installed in the public right-of-way that will be owned, operated and maintained by the City of Overland Park and 2) privately owned streetlighting systems that are installed in the public right-of-way that will not be owned, operated and maintained by the City of Overland Park. Although each of the systems will be discussed, the design guidelines contained herein only apply to systems that are within the public right-of-way that are owned, operated and maintained by the City of Overland Park.
City-Owned, Operated and Maintained Lighting Systems:
All City-owned, operated and maintained lighting systems shall be designed in accordance with the design criteria listed herein and use all pre-approved materials from the City’s Approved Materials List, which is available at City Hall or from the City’s web page http://www.opkansas.org/doing-business/civil-engineering/approved-materials-list/. All lighting systems that are being designed in conjunction with the development of any public street or any developments that require modification of any streetlighting system within the public right-of-way by private consultants working for a developer are required to meet City Standards if the City will assume all ownership, operation and maintenance responsibilities after final acceptance of the project.
Privately Owned, Operated and Maintained Lighting Systems:
All lighting systems within the public right-of-way that have been designated “privately owned” are not required to be constructed using City approved materials. However, the lighting system shall still be designed in accordance with the design criteria listed herein for average maintained light levels and uniformity ratios for the specific functional roadway classification and pedestrian conflict area classification and be constructed in accordance with the National Electric Code, current edition to ensure safe operation.
All proposals for privately owned, operated and maintained lighting systems shall be pre-approved by the Overland Park City Council prior to final plan approval and execution and recording of the City standard maintenance agreement with the Johnson County Records and Tax Administration. If at any time, the homes association or other political subdivision requests the City to assume ownership of the lighting system, the streetlighting maintenance agreement establishes specific items that would need to be addressed before the request would be considered. One requirement is that the current streetlighting system would be have to be replaced with equipment meeting the current City Standards at the sole cost of the current owner.
Privately owned streetlighting systems shall not be permitted to connect to any City-owned streetlighting system, whether it is poles, control centers, cable, junction boxes, etc. unless otherwise stipulated in the maintenance agreement.
The following section addresses the design criteria used for streetlighting in the City of Overland Park depending on the various types of lighting being considered.
Types of Streetlighting Design:
There are two types of streetlighting design used within the City of Overland Park: 1) Continuous lighting and 2) Safety lighting. Continuous streetlighting is required for all collector and thoroughfare designated streets. Safety lighting should be used for residential designated streets. There are specific lighting criteria for each of the two types that will be discussed.
Continuous lighting is defined as streetlighting that is designed to provide specific average maintained light levels and uniformity ratios between adjacent poles in accordance with the functional classification of the street and the corresponding pedestrian conflict area classification. Continuous lighting design shall be required for all collector and thoroughfare street classifications.
Continuous Lighting Design Criteria:
The following streetlighting design criteria will be used for all thoroughfare streets and collector streets, whether improved or unimproved, regardless of the number of through travel lanes and auxiliary lanes, as identified on the latest edition of the City of Overland Park “Official Street Map”, and the “Future Development Master Plan” available from the Planning and Development Services Department.
Functional Street Classifications:
The “major” street classification includes all thoroughfare streets whether divided or undivided; whether improved or unimproved; and whether two-lane, four-lane or six-lane excluding auxiliary left and right turn lanes.
The “collector” street classification includes all super-collector, residential collector streets, apartment streets, commercial streets and industrial streets regardless of the number of lanes; whether improved or unimproved.
Pedestrian Conflict Area:
The “high” pedestrian conflict area includes areas where significant numbers of pedestrians are expected to be on the sidewalks or crossing the streets during darkness. These are typically areas that are in the “Nonresidential Category” zoned for “commercial” or “mixed-use” such as retail areas, near theaters, or major pedestrian generators.
The “medium” pedestrian conflict area includes areas such as libraries, apartments, neighborhood shopping and schools which would be considered in the “Nonresidential Category” and zoned as either “public and semipublic” or in the “Residential Category” that would be zoned as either “high-density” or “medium-high density”.
The “low” pedestrian conflict area includes areas in the “Residential Category” zoned as “medium-density” or “low-density” such as single family residential housing or duplexes.
The maintained averages for luminance, as listed in Table 1, shall be met or exceeded for all continuous lighting designs. The corresponding uniformity ratios and/or veiling luminance ratios shall be equal to or better than those listed in the following table for luminance.
|Street and Pedestrian Conflict Area||Luminance Criteria|
|Functional Street Classification||Pedestrian Conflict Area||Maintained Average (Lavg)
|Uniformity Ratio (Lavg:Lmin)
|Uniformity Ratio (Lmax:Lmin)
|Veiling Luminance Ratio (LVmax:Lavg)|
Safety lighting is defined as lighting that does not provide specific maintained light averages and uniformity ratios between adjacent poles in accordance with the functional classification of the street and corresponding pedestrian conflict area classification. The purpose of this type of lighting design is to provide enough light on the street to enhance the safety of the street users but to avoid over lighting the area. All residential streets shall be designed based on the safety lighting design parameters.
Safety Lighting Design Criteria:
Since June 11, 1979, the City policy has been not to continuously light residential streets. Only" partial" or "safety" lighting is provided. All street lights on residential streets will be installed in conformance with the following basic guidelines.
At Intersections with Other Residential Streets:
In order to provide lighting within the conflict area of two residential streets, a light pole will be installed on one corner of an intersection or opposite the intersection in the case of a T-intersection. (See Figure 1)
On the Same Side as the Sidewalk:
Streetlights should generally be installed on the same side of the street as the sidewalk unless there are significant utility or storm sewer conflicts. Any variance from this practice should be approved by the engineer or project manager.
Near Intersections with Another Pole Oriented in a Different Direction:
Where an intersection has a light pole located at the corner but the luminaire is oriented toward the direction of the primary local street, a second light pole may be located on the secondary local street oriented in the direction of its centerline as long as the light pole is installed greater than 50’ from the back of curb line on the primary local street extended, and it is not on the same corner as the light oriented toward the primary street. (See Figure 1)
Within Cul-de-Sac Bulbs:
A light pole will be installed within the cul de sac bulb when the cul-de-sac street is longer than 200 feet measured from the intersection of the intersecting streets to the center of the cul-de-sac bulb. (See Figure 2)
At Changes of Roadway Alignment:
A light pole will be installed at changes of alignment of 60 or more which are 200 feet or more from an intersection, measured from the intersection of the local street centerlines, to the middle of the curve radius along the centerline of the local street, (See Figure 3)
Mid-block Street Lights:
A minimum number of mid block street lights will be installed in order to achieve a desired pole spacing of approximately 250 feet. The maximum spacing between lights should not exceed 280 feet and the minimum spacing between lights should not be less than 225 feet unless otherwise approved by City staff. Lights should desirably be located on or near a property line and not in front of window lines if avoidable.
Intersections pose the highest conflict area for both vehicles and pedestrians. Therefore, the light levels should be higher for intersections than each individual street.
Intersection Lighting Design Criteria:
The following design criterion has been established for the illumination at street intersections.
|Functional Street Classification||Average Maintained Illumination
at Pavement by Pedestrian Area Classification, (Fc)
|Thoroughfare / Thoroughfare||34.0 / 3.4||26.0 / 2.6||18.0 / 1.8||3.0:1|
|Thoroughfare / Collector||29.0 / 2.9||22.0 / 2.2||15.0 / 1.5||3.0:1|
|Thoroughfare / Local||26.0 / 2.6||20.0 / 2.0||13.0 / 1.3||3.0:1|
|Collector / Collector||24.0 / 2.4||18.0 / 1.8||12.0 / 1.2||4.0:1|
|Collector / Local||21.0 / 2.1||16.0 / 1.6||10.0 / 1.0||4.0:1|
|*Local / Local||NA||NA||NA||NA|
*Intersection lighting analysis is not required for local / local street intersections. The criterion is satisfied if a light is placed at each intersection.
The intersection lighting grid is defined as the quadrilateral whose adjacent sides intersect at the midpoint of the curb radii at the back of curb (See Figure 4). The amount of light should be proportional to the classification of the intersecting streets and be equivalent to the sum of the values used for each separate street. If an intersecting street is illuminated above the recommended value, then the intersection illumination value should be increased proportionately. Intersections of collector and thoroughfare streets with local streets should be illuminated according to Table 2 above criteria has not been established for continuously lighting local streets.