Design Documentation
PI# ####, xxxxxx County
Current Date
Page 2 of 2
(all items in italics and any appropriate text should be replaced with to be project specific)
Revised July 18, 2017
PLACE ON CONSULTANT LETTERHEAD
Current Date
Mr. Mark Lawing
Moreland Altobelli Associates, Inc.
2450 Commerce Avenue, Suite 100
Duluth, GA 30096
RE: Design Documentation for
GDOT project name (match GDOT’s programmed name), xxx County
GDOT PI: #######, Project number CSTEE-###### (if applicable; delete if not assigned)
Dear Mr. Lawing,
This letter describes the design documentation for failing to meet the veiling luminance ratio requirements for the roadway per the RP-8-14 Roadway Lighting guidelines along the project corridor.
Provide a general description of the project including city and street location, scope of work, existing and proposed typical sections, proposed improvements, speed limit, design speed, and amount of TE funds awarded to the project.
Based on IES Publication Roadway Lighting, RP-8-14 Roadway Lighting, the veiling luminance ratio for the roadway should be ##. The proposed lighting was designed meeting the #######, Table ##, for ########### that follow along a roadway per IES Publication Roadway Lighting RP-8-14. In order to meet the requirements for pedestrian lighting, the lighting #### the veiling luminance ratio for the roadway.
The recent Lighting Office review comments required the design to also meet the roadway veiling luminance requirements. Of particular concern was the use of #### watt fixtures mounted on ###’ poles and the potential for glare to traveling motorist. The fixtures are designed to meet the requirements of the pedestrian levels; however the proposed items cannot be designed so that the veiling luminance requirements are met for the roadway calculations. The design spacing and even lowering the wattage to ##### watt has been considered. The proposed fixtures would still not meet roadway veiling luminance requirements.
A Design Variance is not required since veiling luminance is not considered GDOT “standard” criteria. The criteria in RP-8-14 are guidelines that should be followed whenever possible. The project would require a deviation from the RP-8-14 guidelines for roadways to meet the pedestrian lighting requirements.
The project proposes to install #### (##) pedestrian lighting poles along the project corridor. The proposed poles would be #### (##) feet high with ### watt lamps.
Traffic Data:
Current Year: (####) - ####
Design Year: (####) - ####
The following table presents the accident data for the past 4 calendar years:
Year / Angle / Rear End / Side Swipe / Total#### / # / # / # / #
#### / # / # / # / #
#### / # / # / # / #
Total / # / # / # / #
There is no mitigation measures proposed.
Based on the information presented herein, I, as the Engineer of Record submit the design documentation for the referenced project.
Should you have any questions please feel free to contact me at (contact information).
Sincerely,
Name
Title
Company
Attachments to include:
A: Project Location Map (Clearly indicate project location)
B: Typical Sections (Clearly indicate each item which requires design documentation, range of widths is acceptable)
C: Photometric calculations (Clearly indicate each item which requires design documentation with corresponding stations)
Cc: File
Sponsor contact, Sponsor
The above analysis recommending that a Design Variance is not required is in accordance with guidance from the GDOT Office of Design Policy & Support.
Date:
TE Project Manager