Maehl to Mann/Street LightingIAhlDW012K� .
June 7, 2007
93 & Church, LLC
Attn: Howard Mann
100 Hathaway Lane
Kalispell, MT 59901
Re: Street Lighting — Silverbrook Estates
Dear Mr. Mann:
In an earlier letter to Frank Castles, we had requested a deviation to the city standards
on street lighting requirements for the Silverbrook Estates project. The City of Kalispell
Public Works Department currently has a requirement of minimum maintained
illumination of 0.3 foot-candles and a uniformity ratio that shall not exceed 6:1,
throughout the sidewalks along all streets in the city.
What we had proposed to the City was to meet these requirements on Silverbrook
Drive, but on the side streets, have a light standard at each intersection as well as a
light that is a maximum of 750 feet from each intersection. This condition would create
more of a dark sky while providing adequate lighting for pedestrians to walk "to the light"
along Silverbrook Estates' sidewalks. This approach would eliminate a condition that
we strongly feel will result in excessive lighting in a suburban setting. It is our
understanding that the City did not approve this request, and is requiring that all streets
within the subdivision meet the current City lighting requirements.
We recently took some light readings at other subdivisions within Kalispell to see how
the lighting levels within these subdivisions compare with the current standards.
Following are the light levels we measured:
Glacier Commons:
® Directly under a lighting fixture —1.50 foot candles
® Across the street from the fixture — 0.07 foot candles
® Darkest spot between the fixtures — 0.00 foot candles
Granary Ridge:
• Directly under a lighting fixture — 7.41 foot candles
® Across the street from the fixture — 0.55 foot candles
® Darkest spot between the fixtures — 0.14 foot candles
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Buffalo Stage:
® Directly under a lighting fixture — 0.50 foot candles
• Across the street from the fixture — 0.12 foot candles
® Darkest spot between the fixtures — 0.01 foot candles
As can be seen by these measurements, none of these subdivisions would meet the
current City requirement of minimum maintained illumination of 0.3 foot-candles. Based
on the minimum measured foot candles, it does not appear that the City required
uniformity ratio of 6:1 could be achieved either.
Our goal is to provide adequate lighting for pedestrian safety, but not obtrusive to the
homeowners. We feel it would be worthwhile to meet with the City again to see if a
compromise could be reached regarding this issue.
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-2-
Street Liahtinci Ordinances (local residential
Grand Junction, CO
http:/Avww.ci.gran(*d.co. us/CityDeptWebPages/PublicWork&AndUtil itiesfTransportationEngineeringrrEFilesThatLINI(intoD W StoreHere/TEDS/chap8R. pdf
Table 8-1 Average Maintained Illuminance (Foot Candles) on Public Streets
Local Residential Streets *
"On local residential streets, a standard light shall be located at each street intersection, at or near the throat of each
cul-de-sac, and at a maximum spacing of 250 feet measured along the centerline of the roadway. Additional lights may be
required on horizontal curves at other locations."
Portland, OR (page 1 of each)
http:/Avww.portiandonline.com/shared/cftnfimage.cfm?id=36176
City of Portland Street Lighting Standards
Local Service
>_0.006 Lee FL
55 Ave Min (Overall)
<10 Max Min (Overall)
None Max Min (Longitudinal)
hftp://www,portlandonline.com/auditor/index.cfm?a=dgbhe&c=dbbie
1. The adopted Street Lighting Standards also currently recommends an average, horizontal lighting standard (Eh
Ave) of > .2 footcandles for all Local Service (residential) streets, plus a uniformity ratio of < 6 (average to
minimum footcandles) and the ratio of < 20 (maximum to minimum footcandles).
2. A recent study of street light spacing and distribution ratios by Lighting Systems Management for the City of
Portland Bureau of Street Lighting, determined that the Eh Ave. standard or > .2 is acceptable with lights spaced
from 250 feet to 295 feet; however, the < 6 and/or < 20 light distribution ratios on Local Service streets, where
light spacing is 295 feet or more, cannot be obtained. Therefore, the study recommends these latter ratios be
deleted from the Street Lighting Standards.
Bozeman, MIT (page 42-16)
http:/Avww.bozeman.neVbozeman/Chapter 42_March_24 2007_1693.pdf
Table 42-2 Local Street Lights (page 42-16)
1 Street lights are only required at intersections on local streets.
Tempe, AZ (page 5)
http:/ vww.tempe.goviengineering/standard_details/mag_4-8.pdf
T-100.4 Subdivision Lighting (page 5)
"All intersections of residential subdivisions shall have street lighting. Street lighting shall be located on public road rights -
of -way, at the side lot line of the property where possible."
Vancouver, WA
http:/Avww.cityofvancouver. us/TrafficSafety.asp?menuid=10465&submenulD=19947&itemlD=1834D
"The recommended "average luminance level" ranges from 0.3 Candelas per Square Meter for local, residential streets to
1.2 Candelas per Square Meter for Major Arterials in a Commercial area."
Naperville, IL (page 6)
http:/Avww.naperville. i I. uslemplibrary/Se,ction4. p&
Table 4.5.1 Performance Standards for Street Lighting
Local Streets
Max FC 5 3.5
Min FC N/A
Ave FC �: 0.4
Ave/Min Ratio N/A
Bulb Type HIPS
Wattage 100