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