1200 New Jersey Ave., SE

 Washington, D.C. 20590

September 9, 2011

FHWA:HSSI:NArtimovichr:ms:x61331:8/22/11

File: s://directory folder/HSSI/Artimovich/LS74_HAPCO.dotx

cc: HSSI (NArtimovich)

In Reply Refer To:

HSST/LS-74

Mr. Joseph M. Bowman, P.E.

Director of research and Development

Hapco Aluminum Pole Products

26252 Hillman Highway

Abington, VA 24210

Dear Mr. Bowman:

This letter is in response to your requests for the Federal Highway Administration (FHWA) 

acceptance of specific Hapco roadside safety systems for use on the National Highway System 

(NHS).

Name of system: Various breakaway bases and decorative covers for lighting 

and luminaire support posts as described below

Type of system: Breakaway Hardware/Decorative Covers for Various 

Lighting Poles and Luminaire Supports

Test Level: NCHRP Report 350 Test Level 3 (Pendulum Testing)

Testing conducted by: Texas Transportation Institute for Hapco

Date of requests: December 21 and 28, 2010

Request acknowledged: December 22, 2010

You requested that we find five (5) breakaway post designs and three (3) decorative base covers 

used with previously-accepted breakaway post designs acceptable for use on the NHS under the 

provisions of the 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 National Cooperative

Highway Research Program (NCHRP) Report 350 if tested prior to December 31, 2010, and the 

American Association of State Highway and Transportation Officials’ (AASHTO) Manual for 

Assessing Safety Hardware (MASH) if tested after that date. Requirements for breakaway 

supports are contained in the AASHTO Standard Specifications for Structural Supports for 

Highway Signs, Luminaries, and Traffic Signals.

Decision

The Hapco designs/configurations shown in the Test Summary below were tested by TTI and 

found acceptable as indicated. In four cases, design modifications were made to the hardware 

initially used in failed tests and the tests were repeated with successful results.
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Test Descriptions

TTI Tests P15, 16, and 17: These tests were run using HAPCO’s modified breakaway coupling 

67238A (Enclosure 1). Test P15 was not successful because the post did not breakaway and the 

occupant impact velocity was 10.5 m/s, well over the allowable maximum of 5 m/s. It was 

determined the failure was caused by improper installation. Specifically, there was no gap left 

between the breakaway couplings and the foundation/support base. This deficiency was 

corrected and drawings B18836 and B18859 (Enclosures 1A and 1B) were revised to show the 

required gap. Test P16, using a tapered aluminum pole with a 55-foot mounting height, resulted 

in an occupant impact velocity of 3.3 m/s. Test P17, using a tapered aluminum pole with a 50-

foot mounting height, resulted in an occupant impact velocity of 3.2 m/s. The calculated high 
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speed changes in velocity were reported to be 3.6 m/s and 2.4 m/s for Tests P16 and P17, 

respectively.

TTI Tests P18 and 24: Test P18 was run using HAPCO’s Decorative Pedestal (18357) to support 

its Sample-515 lighting pole. This test produced an occupant impact velocity of 5.4 m/s, slightly 

above the maximum value allowed. The Pedestal was modified by drilling two 6 millimeters 

(0.25-inch) holes19 millimeters (0.75 inches) above the base and 146 millimeters (5.75 inches) 

apart. These holes were connected by a 3 millimeters (0.125 inch) slot to create a shear plan 

when the base is impacted by a vehicle. The modified design is designated as part 25090 and is 

shown as Enclosure 2. Test P24 was a test of the modified design with the tapered aluminum 

tube shown in Enclosure 2A. The low-speed occupant impact velocity was reported to be 3.6 

m/s and the calculated high-speed OIV was reported to be 2.4 m/s.

TTI Tests P19 and 25: Test P19 was run using HAPCO’s Decorative Pedestal (17642) to support 

its Sample-513 lighting pole. This test resulted in an unacceptable low-speed OIV of 5.9 m/s. 

The Pedestal was modified by drilling two 6 millimeters (0.25-inch) holes 22 millimeters (0.875 

inches) above the base and 152 millimeters (6 inches) apart. These holes were connected by a 3 

millimeters (0.125 inch) slot to create a shear plan when the base is impacted by a vehicle. The 

modified design is designated as part 25088 and is shown as Enclosure 3. Test P25 was a test of 

the modified design with the tapered aluminum tube shown in Enclosure 3A. The low-speed 

occupant impact velocity was reported to be 5.0 m/s and the calculated high-speed OIV was 

reported to be 2.6 m/s.

TTI Test P20: Test P20 was run on HAPCO’s Sample-514 lighting pole supported by a 

Decorative Pedestal made from 356-T6 aluminum and modified from the previously-accepted 

part 13172 to add a machined groove. The modified design, part 25089, is shown as Enclosure 4 

and the tested set-up is Enclosure 4A. Upon impact with the pendulum, the pole separated from 

the base. Although this separation is not desirable, the test video showed that the sheared pole 

continued to move away from the impact point and thus was not likely to impact the windshield 

of a vehicle in an actual crash. The reported OIV was 3.1 m/s and the calculated high-speed 

value was 3.1 m/s

TTI Test P21: This test was conducted to verify acceptable crash performance of a decorative 

base cover installed over a previously-accepted breakaway design. This cover is a two-piece cast 

aluminum design bolted together with 10-millimeters (0.375 inch) nylon hex screws and nuts to 

ensure separation of the two halves in a crash. The reported low-speed OIV was 2.9 m/s and the 

calculated high-speed value was 1.4 m/s. The tested set-up with pole Sample-512 is shown in 

Enclosure 5.

TTI Test P22: This test was also conducted to verify acceptable crash performance of a 

decorative base cover installed over a previously-accepted breakaway design. This cover is a 

two-piece cast aluminum design bolted together with 10-millimeters (0.375 inch) nylon hex 

screws and nuts to ensure separation of the two halves in a crash. The reported low-speed OIV 

was 3.3 m/s and the calculated high-speed value was 1.8 m/s. The tested set-up with pole 

Sample-511 is shown in Enclosure 6.
4

TTI Tests P23and 26: Test P23 was conducted to verify acceptable crash performance of a 

decorative base cover installed over a previously-accepted breakaway design. This cover was 

also a two-piece aluminum design bolted together with 10-millimeters (0.375 inch) nylon hex 

screws and nuts to ensure separation of the two halves in a crash. The test failed with a reported 

low-speed OIV of 6.0 m/s. Post-impact analysis indicated that the previously-accepted 

breakaway base failed to yield as designed because of an oversized fillet weld. This error was 

corrected and the system was re-tested under test P26. In the second test, the reported low-speed 

OIV was 2.9 m/s and the calculated high-speed value was 1.7 m/s. The tested set-up with pole 

Sample-510 is shown in Enclosure 7. Note #3 was added to this drawing to address the 

aforementioned weld problem.

TTI Tests P27 and 28: Both of these tests used HAPCO’s Modular T-base Assembly as shown in 

Enclosures 8 and 8A. Test P27 used a 55-foot luminaire mounting height as shown in Enclosure 

8B and Test P28 shown in Enclosure 8C used a similar set-up, but with a 50-foot mounting 

height. For Test P27, the low-speed actual and high-speed calculated OIV values were 4.5 m/s 

and 4.4 m/s, respectively. For Test P28, these values were 4.8 m/s and 3.3 m/s, respectively. 

Although both test installations used a 14.5-inch bolt circle, you requested the Modular T-base 

be accepted for use with bolt circles from 10 inches to 17.5 inches. For a traditional cast 

aluminum transformer base, FHWA acceptance is limited to the largest diameter bolt circle that 

was actually tested. However, in your design, each “leg” of the breakaway structure functions 

independently of the remaining three. Therefore, a bolt “circle” ranging from 10 inches to 17.5 

inches is acceptable.

Crash Testing

Pendulum testing was conducted on the test articles described above by the Texas Transportation 

Institute (TTI) at their outdoor pendulum testing facility. All tests were conducted according to 

NCHRP 350 test designation 3-60. The FHWA accepts pendulum tests as surrogates for this 

low-speed small car test. The FHWA also allows the results of the high speed tests to be 

estimated using data from the low-speed pendulum test in combination with an analytical 

extrapolation method described in the FHWA memorandum “Identifying Acceptable Highway 

Safety Features” dated on July 25, 1997.

Findings 

For all eight test articles, the low speed test results and the high speed test extrapolation analysis 

resulted in change in velocity values less than the upper limit of 5.0 m/s.

It should be noted that the pole, luminaire arm, and clamshell base covers must meet the 

conditions and limitations of TRANSPO Industries breakaway couplings identified in FHWA 

acceptance letter LS-45B particularly the followings:

• All supports shall be mounted to a structural concrete foundation that will not move in 

the soil if the support is struck be a vehicle.

• Luminaire mounting height should not exceed 15.7 meters (55 feet).

• Mass of pole, mast arm, luminaire and other hardware above the couplings shall not 

exceed 454 kg (1000 lbs.).
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Therefore, the systems described above and detailed in the enclosed drawings are acceptable for 

use on the NHS under the range of conditions tested, when such use is acceptable to a highway 

agency.

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

• This acceptance is limited to the crashworthiness characteristics of the tested features and 

does not cover their structural features, such as resistance to wind loads. 

• Any design or material changes that may adversely influence the crashworthiness of the

Dent system will require a new acceptance letter.

• Should the FHWA discover that the qualification testing was flawed, that in-service

performance reveals unacceptable safety problems, or that the system being marketed is 

significantly different from the version that was crash tested, we reserve the right to 

modify or revoke our acceptance.

• You will be expected to supply potential users with sufficient information on design and 

installation requirements to ensure proper performance.

• You will be expected to certify to potential users that the hardware furnished has 

essentially the same chemistry, mechanical properties, and geometry as that submitted for 

acceptance, and that it will meet the crashworthiness requirements of the FHWA and the 

NCHRP Report 350.

• To prevent misunderstanding by others, this letter of acceptance is designated as number 

LS-74 and shall not be reproduced except in full. This letter and the test documentation 

upon which it is based are public information. All such letters and documentation may be 

reviewed at our office upon request.

• The Hapco products identified above are patented products and considered proprietary. 

If proprietary systems are specified by a highway agency for use on Federal-aid projects, 

except exempt, non-NHS projects, (a) they must be supplied through competitive bidding 

with equally suitable unpatented items; (b) the highway agency must certify that they are 

essential for synchronization with the existing highway facilities or that no equally 

suitable alternative exists; or (c) they must be used for research or for a distinctive type of 

construction on relatively short sections of road for experimental purposes. Our 

regulations concerning proprietary products are contained in Title 23, Code of Federal 

Regulations, Section 635.411.

• This acceptance letter shall not be construed as authorization or consent by the FHWA to 

use, manufacture, or sell any patented system for which the applicant is not the patent 

holder. The acceptance letter is limited to the crashworthiness characteristics of the 

candidate system, and the FHWA is neither prepared nor required to become involved in 

issues concerning patent law. Patent issues, if any, are to be resolved by the applicant.

Sincerely yours,

Michael S. Griffith 

Office of Safety Technologies 

Office of Safety 

Enclosures