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FHWA Home / Safety / Roadway Departure / Safety Eligibility Letter

Safety Eligibility Letter LS-69

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U.S. Department of Transportation
Federal Highway Administration

1200 New Jersey Ave. S.E.
Washington, D.C. 20590

October 29, 2009

In Reply Refer To: HSSD/LS-69

Mr. Greg Mercier
Director of Design Engineering
Hapco
26252 Hillman Highway
Abingdon, VA 24210

Dear Mr. Mercier,

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).

Name of device: Hapco decorative pole B15366 (casting 79419)
Type of device:Luminaire Support
Test Level:Test Level 3 (TL-3)
Testing conducted by:Texas Transportation Institute (TTI)
Date of request:September 16, 2009
Date of follow-up:October 21, 2009

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.”

Requirements
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.

Description
The Hapco decorative pole B15366 (casting 79419) luminaire support was tested at the TTI outdoor pendulum testing facility. The base of the lighting pole was cast aluminum (alloy 356-T6) with a round base tapered to a height of 29 ¼ inches. A 6-inch outside diameter tapering to a 3-inch outside diameter aluminum tube (alloy 6063-T6) with ¼ inch wall thickness and 17 foot 7 inch long was screwed and welded to the tapered shape, giving a total height of 20 feet. A cast aluminum adapter ring was placed on top of the pole to accommodate the round light. The weight of the pole with base was 173 pounds and the round light was 17 pounds, totaling a weight of 190 pounds. The base was welded to a 10-inch diameter and 6-foot long aluminum tube with wall thickness of 0.156 inches. Drawings of the Hapco decorative pole B15366 (casting 79419) luminaire support are enclosed.

Crash Testing
Your company’s decorative lighting pole was tested at TTI’s outdoor pendulum testing facility, as a surrogate for full-scale crash testing. The pendulum bogie was built according to 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.

A low speed pendulum test was conducted on your company’s decorative lighting supports. A summary of the test results are enclosed. The decorative lighting pole met the NCHRP Report 350 occupant risk criteria. In addition, TTI extrapolated the high-speed performance of the lighting pole installation from the low speed pendulum test. I agree that the test article appears to perform appropriately to make such high-speed extrapolations. All high speed extrapolations yield lower change in velocity values than the paired low speed pendulum test.

In the test with the Hapco decorative pole B15366 (casting 79419), the base fractured at ground level and at the connection to the tapered aluminum pole. The base fracturing at ground level satisfies the FHWA limit of maximum 3.9-inch stub height remaining after a support breaks away.

Findings
In summary, the Hapco decorative pole B15366 (casting 79419) 20 foot decorative lighting pole as described above, meets the appropriate evaluation criteria for a NCHRP 350 TL-3 device and may be used at all appropriate locations on the NHS when selected by the contracting authority. The Hapco decorative pole B15366 (casting 79419) is accepted with luminaire heights up to 20 feet, shafts up to ¼ inch wall thickness with diameters up to 6 inches, and embedment lengths not less than 6 feet.

Standard provisions
Please note the following standard provisions that apply to FHWA letters of acceptance:

 

Sincerely yours,

Signature of David A. Nicol, P.E.

David A. Nicol, P.E.
Director, Office of Safety Design
Office of Safety

Enclosures

Page last modified on September 27, 2013.
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