Loading...
Item 9AM E M O R A N D U M (April 7, 2009) To: Shana Yelverton, City Manager From: Robert H. Price, P.E., Public Works Director Subject: Consider approving staff recommendation of overhead street lighting selection for Kirkwood Boulevard, North Kimball Avenue and North White Chapel Boulevard Action Requested: Consider approving staff recommendation of overhead street lighting selection for Kirkwood Boulevard, North Kimball Avenue and North White Chapel Boulevard. Background Information: Over the last several weeks, the City staff has conducted Council workshops to present street light options for arterial streets. Staff will recap and summarize the workshop discussions and present a recommendation for consideration by the City Council. Adequate street lighting is normally provided in accordance with standard engineering practice when arterial streets are constructed or improved. Adequate arterial street lighting is defined by the American Association of State Transportation Officials (AASHTO) as providing average minimum 0.8 foot- candle illumination or average desired 1.0 foot-candle average illumination on the pavement. In addition to the standards defined by AASHTO, the City of Southlake lighting ordinance (Ordinance 693-B) limits the intensity of lighting to 0.2 foot-candle average illumination as measured at the property line in areas with single or two family residential adjacency. The City and other governmental agencies are exempt from the lighting ordinance when installing lighting for safety or traffic control purposes, but City staff has used this as a guiding standard and endeavored not to unnecessarily exceed this threshold when possible. Three projects have surfaced recently that cause City staff to consider installation of arterial street lighting. The first is the Gateway Church project. Although a private development project, the Church will be constructing and lighting a portion of an arterial street (Kirkwood) and two local/collector streets (Grace Lane and Blessed Way) through the project. As with most development projects, the Church desired to light the streets within their development project. In this case, the streets are arterial and collectors rather than the typical neighborhood streets and will be lit to a higher standard. The standard procedure is for the developer to select a street light pole and fixture standard and to submit a lighting plan to the City for comment, revision, and approval. The Church, in accordance with their developer’s agreement, would pay for the initial light installation as well as for the initial two years of operation and maintenance expense. Gateway Church has proposed to light the above mentioned streets with painted steel poles and the “Gullwing” light fixture. The other two projects are the North Kimball Avenue widening project and the White Chapel Boulevard widening project. Both streets are being designed as four lane divided urban arterials in the City capital improvement program. Because the street light standard question arose with the consideration of Kirkwood Boulevard through the Gateway project, City staff recommended to the City Council that other arterial streets projects should include street lighting when they are constructed to recommended Thoroughfare Plan standards. Staff considered several options when deliberating street lighting design and selection of lighting fixtures. The first consideration was the type and appearance of the poles. Staff considers the painted steel pole to be much more desirable than the galvanized steel pole and has consistently made that recommendation. To achieve adequate lighting levels between the 0.8 and 1.0 foot-candle standard, staff proposes to use a 30’ median mounted pole with dual fixtures and 250 watt high pressure sodium lights. The next step is to determine a fixture that would provide this lighting level on the pavement without unnecessarily exceeding the 0.2 foot-candle standard at the residential property line called for in our lighting ordinance. Because it is desirable to maintain a consistent light fixture in the City, and given the proximity of the North Kimball Avenue project to Kirkwood Boulevard in the Gateway project, staff evaluated the “Gullwing” fixture to determine if it would be suitable for other arterial lighting applications in the City. The lighting footprint of the “Gullwing” is slightly above the 0.2 foot-candle limit at the right of way line on a standard width arterial street, but has a pronounced bulge that will exceed the 0.2 foot-candle limit and approach 0.5 foot- candle at the right of way line. Using the “Gullwing” fixture on Kirkwood Boulevard is acceptable because there is no residential adjacency that would trigger the lighting ordinance limitation. However, most other arterials have residential adjacency that would probably preclude the use of the “Gullwing” fixture. Staff also considered using a “shoebox” fixture. This is a standard fixture in the menu of options provided by Oncor Electric provider. Like the “Gullwing” fixture, the “shoebox” fixture provided adequate lighting on the pavement between 0.8 and 1.0 foot-candles and slightly exceeded the 0.2 foot- candles at the right of way line, but did not have the bulge produced by the “Gullwing”. As mentioned above, the “shoebox” is a standard fixture in the Oncor Electric menu of options. Southlake has two electric providers and most areas of the City are able to select between the two. Tri-County Electric is a co-operative provider and is much smaller than Oncor. In addition to being the larger provider, Oncor is more heavily regulated. What this means in this instance is that Tri-County is better able to tailor their options to the desires of the customer. Oncor, on the other hand, will have to consider alternative street light options in light of system wide considerations and the tariffs set by the Public Utility Commission. Oncor may be able to provide a fixture that is not currently on their menu, but it would require a formal request from the City and may require a lengthy evaluation period by Oncor to determine if the proposed fixture is appropriate. If Oncor, after internal deliberation, decides to add another street light fixture to their menu, they may have to go to the PUC for a tariff rate adjustment. This process could take several months to longer than a year. The two electric providers have the “shoebox” fixture, as well as the “cobra head” fixture, on their menu of standard arterial lighting options. Staff did not consider the “cobra head” fixture as suitable for use in Southlake. Tri-County Electric has agreed to provide and install the Gullwing fixture for the Kirkwood Boulevard project upon the City’s approval. Kirkwood Boulevard will have only commercial/institutional adjacency through the Gateway project. Also, the section of Kirkwood Boulevard through the proposed Carillon project has wider parkway buffer zones adjacent to the arterial which would mitigate, if not eliminate, lighting spillover problems. The City Council can expect commercial adjacency between Gateway and Carillon and can specify the parkway widths and land use west of White Chapel. Therefore, it is possible to use the “Gullwing” fixture on most of the entire length of Kirkwood Boulevard from Kimball Avenue west without an issue with light spillover to adjacent residential property. Because of the difficulty of getting a new standard fixture added to the Oncor menu, staff did not expand review of possible fixture designs beyond the “Gullwing” and “shoebox” styles. After considering the options as outlined above and comments received at previous workshops, Staff makes the following recommendations: Kirkwood Boulevard – Use median mounted 30’ painted steel poles with “Gullwing“ fixtures and 250 watt high pressure sodium lights Grace Lane and Blessed Way – Use median and/or parkway mounted 30’ painted steel poles with “Gullwing“ fixtures and 250 watt high pressure sodium lights North Kimball Avenue– Use median mounted 30’ painted steel poles with “shoebox“ fixtures and 250 watt high pressure sodium lights North White Chapel Boulevard – Use median mounted 30’ painted steel poles with “shoebox“ fixtures and 250 watt high pressure sodium lights Financial Considerations: Proposed changes to the standard menu of arterial lighting options may require modified street lighting agreements, depending on the cost and availability of the fixture being proposed. Strategic Link: Theinstallation of standard street lights on arterial streets when they are constructed to the standards recommended in the 2025 Plan links to the city’s strategy map relative to the focus areas of Safety and Infrastructure. The specific corporate objectives that are met by the construction of this new transportation infrastructure include: Providing the highest standards of safety and security; travel convenience within the City and region, investing to provide and maintain high quality public assets, and providing high quality customer service. Citizen Input/ Board Review: None Legal Review: None Alternatives: The Councilmay approve the staff recommendations, amend the recommended street lighting standards or instruct staff to not install lighting at this time. Supporting Documents: None Staff Recommendation: Consider approving staff recommendation of overhead street lighting selection for Kirkwood Boulevard, North Kimball Avenue and North White Chapel Boulevard Staff Contact: Robert H. Price, P.E., Public Works Director Gordon J. Mayer, Jr., P.E., City Engineer Michael James, P.E., Civil Engineer