Federal Highway Administration
1200 New Jersey Ave., S.E.
May 30, 2008
Mr. Travis Rock
Dynamic Lighting Inc.
5220 Shank Rd
Houston, TX 77581
Dear Mr. Rock:
This letter is in response to your request for Federal Highway Administration (FHWA) acceptance of a roadside safety device for use on the National Highway System (NHS).
You requested that we find this device acceptable for use on the NHS under the provisions of National Cooperative Highway Research Program (NCHRP) Report 350 “Recommended Procedures for the Safety Performance Evaluation of Highway Features.”
Roadside safety devices should meet the guidelines contained in the NCHRP Report 350, "Recommended Procedures for the Safety Performance Evaluation of Highway Features". FHWA Memorandum “ACTION: Identifying Acceptable Highway Safety Features” of July 25, 1997 provides further guidance on crash testing requirements of luminaire supports.
The following two Dynamic Lighting decorative luminaire installations were tested at the TTI outdoor pendulum testing facility:
Dynamic Lighting pole base 26706B was connected to a fluted luminaire and attached to a Dynamic Lighting ground stub FDBE36 as shown in the enclosed drawings. The 36-inch (0.91 m) ground stub was installed in NCHRP 350 standard soil. The total height of the base and pole is 13 feet 10 inches (4.22 m). The base is cast aluminum (alloy A319) with an 11-1/2 inch (292.1 mm) square base bottom tapering to an octagonal shape for a base height of 25-1/4 inches (641.35 mm). Drawings of the Dynamic Lighting pole cast base assembly 26706B, pole, and ground stub FDBE36 are enclosed. The Dynamic Lighting pole base 26706B with luminaire pole was also tested while attached to a rigid steel reaction plate to simulate a fixed anchorage.
Dynamic Lighting pole base 26706A was connected to a fluted luminaire and attached to a rigid steel reaction plate to simulate a fixed anchorage. The total height of the base and pole is 15 feet 6 inches (4.72 m). The base is cast aluminum (alloy A319) with a 17 inch (431.8 mm) diameter base bottom tapering to a 5 inch (127 mm) diameter and overall base height is 17-1/4 inches (438.15 mm). A drawing of the Dynamic Lighting pole cast base assembly 26706A and pole is enclosed.
Your company’s decorative lighting poles were tested at TTI’s outdoor pendulum testing facility as a surrogate for full-scale crash testing. The pendulum bogie was built according the specifications of the Federal Outdoor Impact Laboratory's (FOIL) pendulum, and the frontal crush of the aluminum honeycomb nose of the bogie simulated the crush of an actual vehicle. Tests with pendulums are acceptable for most breakaway supports, exceptions being base bending or yielding supports.
Three low speed pendulum tests were conducted on your company’s decorative lighting supports, one test on each of the pole installations. Summaries of test results are enclosed. All Decorative Lighting Poles met the NCHRP Report 350 occupant risk criteria.
In tests with Dynamic Lighting pole base 26706B (surface mount and embedded ground stub FDBE36) and Dynamic Lighting pole base 26706A, the base separated from the ground and the lighting pole separated from the decorative base section. The base fractured at ground line and this performance satisfies the FHWA limit of maximum 3.9 inch (100 mm) stub height remaining after a support breaks away.
In summary, the Dynamic Lighting pole base 26706B (with the surface mount or the embedded ground stub FDBE36) and Dynamic Lighting pole base 26706A with decorative lighting poles, meet the appropriate evaluation criteria for a NCHRP 350 TL-3 device. They may be used at all appropriate locations on the NHS when selected by the contracting authority, subject to the provisions of Title 23, Code of Federal Regulations, Section 635.411 as they pertain to proprietary products. The Dynamic Lighting pole base 26706B (surface mount and embedded ground stub FDBE36) is accepted with luminaire pole mounting heights up to13 feet 10 inches (4.22 m), with shafts up to 0.188 inch (4.78 mm) wall thickness, and diameters up to 4 inches (101.6 mm). The ground stub FDBE36 must have a 0.188 inch (4.78 mm) wall thickness and embedment length of at least 36 inches (0.91m) in NCHRP standard soil. The Dynamic Lighting pole base 26706A is accepted with luminaire pole heights up to 15 feet 6 inches (4.72 m), with shafts up to 0.155 inch (3.94 mm) wall thickness, and with diameters up to 5 inches (127 mm).
Please note the following standard provisions that apply to FHWA letters of acceptance:
David A. Nicol, P.E.
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