1200 New Jersey Ave., SE

Washington, D.C. 20590

FHWA: HSST: WLongstreet: ms: x60087:6/15/11

File: h://directory folder/HSST/LS-73MwRSFCouplings#6.docx

cc: HSST Will Longstreet 

June 23, 2011

In Reply Refer To:

HSST/LS-73

Mr. Dean L. Sicking, Ph.D., P.E.

Director, Midwest Roadside Safety Facility

University of Nebraska - Lincoln

2200 Vine Street

130 Whittier research Center

Lincoln, NE 68583-0583

Dear Mr. Sicking:

This letter is in response to Mr. Scott Rosenbaugh’s request for the Federal Highway 

Administration (FHWA) acceptance of a design for the Illinois DOT breakaway brass couplings 

for use with luminaire supports on the National Highway System (NHS).

Name of system: Brass Breakaway Couplings

Type of system: Breakaway Hardware for Aluminum and Steel Luminaire Supports

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

Testing conducted by: Midwest Roadside Safety Facility

Date of requests: December 23, 2010

Date of completed package: December 23, 2010

Request initially acknowledged: December 27, 2010

You requested that we find a brass breakaway coupling 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 both of these documents and in the AASHTO Standard Specifications 

for Structural Supports for Highway Signs, Luminaries, and Traffic Signals.

Decision

The following component was found acceptable, with details provided below:

• Brass Breakaway Coupling Hardware for Aluminum and Steel Luminaire Supports
2

Test Descriptions

A total of seven tests were performed (i.e., Test Nos. BBC-1 through BBC-7) to verify the crash

performance of the breakaway couplings. Since the occupant risk factors in the first two tests 

(BBC-1 and BBC-2) exceeded the allowable maximum values, the brass couplings were 

redesigned for the next three tests.

Tests BBC-3 and BBC-4 both tested heavy steel poles, the first test using the modified brass 

couplers (Version 2) and the second using a previously-accepted double-neck coupling for 

comparison purposes. While both of these tests satisfied the low-speed pendulum occupant risk 

values, both exceeded the extrapolated maximum allowable change in velocity. 

Test BBC-5 tested the crashworthiness of a 30-foot (9.1-meter) aluminum pole with a single 

mast arm mounted on the modified brass breakaway couplings (Version 2). The low-speed 

change in velocity (ΔVL) and the extrapolated high-speed change (ΔVH) were believed to be 

conservative estimates for the final (Version 3) breakaway brass coupling design. The only 

difference between Version 2 and the Version 3 couplings was the distance between the notch 

and top of the coupling as well as the overall coupling height. This change lowered its impact 

resistance and effectively shortened the time to fracture. Therefore, a test of the same pole/mast 

arm configuration using the Version 3 breakaway brass couplings would result in lower ΔVL and 

ΔVH values than those in test BBC-5. Subsequently, the Version 3 brass couplings were deemed 

to meet the TL-3 impact safety standards when utilized with a 30-foot (9.1-meter) nominal 

height, aluminum luminaire pole system.

Test BBC-6 specified Version 3 brass couplings used to support a 45-foot (13.7-meter) nominal 

height, steel luminaire pole system. During the impact event, all four couplings fractured, 

leaving stub heights of 13⁄4 inch (38 millimeter). In the test, the pole system rotated away from 

its initial attachment location. The measured ΔVL was 13.25 feet/second (4.04 meters/second), 

which satisfied the NCHRP Report No. 350 maximum allowable limit of 16.4 feet/second (5.0 

meters/second). However, the extrapolated ΔVH was calculated to be 16.85 feet/second (5.14 

meters/second). As a result, the 45-foot (13.7-meter) nominal height, steel luminaire system did 

not meet the TL-3 evaluation criteria.

Test BBC-7 used an aluminum luminaire pole with a 55-foot (16.8-meter) nominal mounting 

height. The pole shaft was 50-foot (15.2-meter) long, 5/16-inch (8-millimeter) thick, and had top 

and bottom diameters of 6 inches (152 millimeters) and 10 inches (254 millimeters), 

respectively. The base plate was 11⁄4-inch (32-millimeters) thick by 14-inch (356-millimeters) 

square. The bolt circle was 15 inches (381 millimeters) in diameter. Dual 15-foot (4.6-meter) 

truss arms were attached to top of the pole. The pole weighed 536 pounds (243 kilograms), 

while the arms with simulated luminaire weighed 219 pounds (99 kilograms). The total weight 

of the luminaire pole system was 755 pounds (343 kilograms). In this test, the breakaway brass 

couplings (Version 3) fractured and allowed the aluminum pole system to rotate away from its 

initial ground attachment location. The remaining coupling stub heights were 13⁄4 inch (38 

millimeter), satisfying the 4-inch (100-millimeter) limit. Both the measured ΔVL and the 

extrapolated ΔVH satisfied the NCHRP Report No. 350 maximum allowable limit of 16.4 

feet/second (5.0 meters/second). Therefore, based on the results of tests BBC-5 and BBC-7, 

aluminum luminaire poles of nominal heights between 30 feet (9.1 meters) and 55 feet
3

(16.8 meters), with minimum wall thicknesses of 1⁄4-inch (6.4 millimeters), and weighs equal to 

or less than 755 pounds (343 kilograms) should be acceptable for use with the Version 3 

breakaway brass couplings.

For test no. BBC-6, the Version 3 brass couplings were used to support a 45-foot (13.7-meter)

nominal height, steel luminaire pole system. During the impact event, all four couplings 

fractured, leaving stub heights of 13⁄4-inch (38 millimeter). In the test, the pole system rotated 

away from its initial attachment location. The measured ΔVL was 13.25 feet/second (4.04 

meters/second), which satisfied the NCHRP Report No. 350 maximum allowable limit of 16.4 

feet/second (5.0 meters/second). However, the extrapolated ΔVH was calculated to be 16.85 

feet/second (5.14 meters/second). As a result, the 45-foot (13.7-meter) nominal height, steel

luminaire system did not meet the TL-3 evaluation criteria.

To identify the largest steel luminaire poles that can be used in combination with the breakaway 

brass couplings, further analysis was undertaken using the high-speed extrapolation equation to 

predict the ΔVH for different size poles. Steel luminaire pole configurations with varying 

thicknesses and heights were analyzed to determine the extrapolated high-speed, change in

longitudinal velocity (ΔVH). These extrapolated values were compared to the maximum

allowable limit of 16.4 feet/second (5.0 meters/second) in order to determine whether specific 

poles were acceptable for use with the brass couplings. During this study, the luminaire arms, 

base plate, and pole base diameter were held constant to the dimensions and weights

corresponding to those used in test no. BBC-6. Thus, only the shaft thickness and heights were 

altered. This analysis yielded the maximum shaft height for poles with a wall thickness ranging 

between 7 gauge (4.55 millimeter) and 11 gauge (3.03 millimeter). For a 7-gauge (4.55-

millimeter) wall thickness or the same thickness as used in test no. BBC-6, the maximum shaft 

height was determined to be 36 feet (11.0 m), with a nominal height of 41 feet (12.5 meters). The 

results from this analysis for all wall thicknesses are shown in the Table below.

Crash Testing

Pendulum testing was conducted on the test articles described above by the Midwest Roadside 

Safety Facility with their FHWA-approved Valmont/MwRSF-UNL pendulum. 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. 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 

The breakaway couplings proposed by the ILDOT and subsequently modified during your 

research effort were fabricated from ASTM B16, free-cutting brass, drilled and tapped for 1 inch

(25 millimeter) – 8UNC threaded bars, and had a circumferential notch cut around its outer 

surface to induce fracture. 

The final design (Version 3) as developed under your testing program for the Illinois DOT is 

shown as an enclosure to this letter and is acceptable for use on the NHS. The applicable 

luminaire pole systems for use with the Brass Breakaway Couplings when used to support 
4

aluminum or steel poles with maximum base diameters of 10 inches (254 millimeters) and within 

the height and weight ranges are shown in the following table.

Pole Type Thickness

Base

Diameter

Nominal

Height

System

Weight

Min. Max. Min. Max. Min. Max.

Aluminum ≥ 1⁄4 in.

(≥ 6.4 mm)

8 in.

(203 mm)

10 in.

(254 mm)

30 ft

(9.1 m)

55 ft

(16.8 m)

259 lb

(118 kg)

755 lb

(343 kg)

Steel

7 gauge

(4.55 mm) NA 10 in.(254 mm)

30 ft

(9.1 m)

41 ft

(12.5 m)

259 lb

(118 kg)

872 lb

(396 kg)

8 gauge

(4.18 mm) NA 10 in.(254 mm)

30 ft

(9.1 m)

46 ft

(14.0 m)

259 lb

(118 kg)

871 lb

(395 kg)

9 gauge

(3.80 mm) NA 10 in.(254 mm)

30 ft

(9.1 m)

51 ft

(15.5 m)

259 lb

(118 kg)

856 lb

(389 kg)

10 gauge

(3.42 mm) NA 10 in.(254 mm)

30 ft

(9.1 m)

59 ft

(18.0 m)

259 lb

(118 kg)

841 lb

(382 kg)

11 gauge

(3.03 mm) NA 10 in.(254 mm)

30 ft

(9.1 m)

60 ft

(18.3 m)

259 lb

(118 kg)

782 lb

(355 kg)

The final design of the brass coupling Version 3 may be used on the NHS in combination with 

any of the poles as indicated in this correspondence. As noted in your test report, poles with 

diameters larger than 10 inches (254 millimeters) must be analyzed independently using the 

proposed systems’ mass distribution and the extrapolation formula to calculate the high speed 

occupant impact velocities. Because the mast arms were held constant for all tests, any mass arm 

configurations other than truss-type luminaire arms also need to be analyzed on a case-by-case 

basis. 

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 letter provides an AASHTO/ARTBA/AGC Task Force 13 designator 

that should be used to create a new or updated Task Force 13 drawing.

• 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

Illinois DOT breakaway brass couplings 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.
5

• 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-73 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 Brass Couplings identified above are to be patented products and therefore are 

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

Director, Office of Safety Technologies 

Office of Safety

Enclosure
 1200 New Jersey Ave., SE

Washington, D.C. 20590

June 23, 2011

In Reply Refer To:

HSST/LS-73

Mr. Dean L. Sicking, Ph.D., P.E.

Director, Midwest Roadside Safety Facility

University of Nebraska - Lincoln

2200 Vine Street

130 Whittier research Center

Lincoln, NE 68583-0583

Dear Mr. Sicking:

This letter is in response to Mr. Scott Rosenbaugh’s request for the Federal Highway 

Administration (FHWA) acceptance of a design for the Illinois DOT breakaway brass couplings 

for use with luminaire supports on the National Highway System (NHS).

Name of system: Brass Breakaway Couplings

Type of system: Breakaway Hardware for Aluminum and Steel Luminaire Supports

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

Testing conducted by: Midwest Roadside Safety Facility

Date of requests: December 23, 2010

Date of completed package: December 23, 2010

Request initially acknowledged: December 27, 2010

You requested that we find a brass breakaway coupling 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 both of these documents and in the AASHTO Standard Specifications 

for Structural Supports for Highway Signs, Luminaries, and Traffic Signals.

Decision

The following component was found acceptable, with details provided below:

• Brass Breakaway Coupling Hardware for Aluminum and Steel Luminaire Supports
2

Test Descriptions

A total of seven tests were performed (i.e., Test Nos. BBC-1 through BBC-7) to verify the crash

performance of the breakaway couplings. Since the occupant risk factors in the first two tests 

(BBC-1 and BBC-2) exceeded the allowable maximum values, the brass couplings were 

redesigned for the next three tests.

Tests BBC-3 and BBC-4 both tested heavy steel poles, the first test using the modified brass 

couplers (Version 2) and the second using a previously-accepted double-neck coupling for 

comparison purposes. While both of these tests satisfied the low-speed pendulum occupant risk 

values, both exceeded the extrapolated maximum allowable change in velocity. 

Test BBC-5 tested the crashworthiness of a 30-foot (9.1-meter) aluminum pole with a single 

mast arm mounted on the modified brass breakaway couplings (Version 2). The low-speed 

change in velocity (ΔVL) and the extrapolated high-speed change (ΔVH) were believed to be 

conservative estimates for the final (Version 3) breakaway brass coupling design. The only 

difference between Version 2 and the Version 3 couplings was the distance between the notch 

and top of the coupling as well as the overall coupling height. This change lowered its impact 

resistance and effectively shortened the time to fracture. Therefore, a test of the same pole/mast 

arm configuration using the Version 3 breakaway brass couplings would result in lower ΔVL and 

ΔVH values than those in test BBC-5. Subsequently, the Version 3 brass couplings were deemed 

to meet the TL-3 impact safety standards when utilized with a 30-foot (9.1-meter) nominal 

height, aluminum luminaire pole system.

Test BBC-6 specified Version 3 brass couplings used to support a 45-foot (13.7-meter) nominal 

height, steel luminaire pole system. During the impact event, all four couplings fractured, 

leaving stub heights of 13⁄4 inch (38 millimeter). In the test, the pole system rotated away from 

its initial attachment location. The measured ΔVL was 13.25 feet/second (4.04 meters/second), 

which satisfied the NCHRP Report No. 350 maximum allowable limit of 16.4 feet/second (5.0 

meters/second). However, the extrapolated ΔVH was calculated to be 16.85 feet/second (5.14 

meters/second). As a result, the 45-foot (13.7-meter) nominal height, steel luminaire system did 

not meet the TL-3 evaluation criteria.

Test BBC-7 used an aluminum luminaire pole with a 55-foot (16.8-meter) nominal mounting 

height. The pole shaft was 50-foot (15.2-meter) long, 5/16-inch (8-millimeter) thick, and had top 

and bottom diameters of 6 inches (152 millimeters) and 10 inches (254 millimeters), 

respectively. The base plate was 11⁄4-inch (32-millimeters) thick by 14-inch (356-millimeters) 

square. The bolt circle was 15 inches (381 millimeters) in diameter. Dual 15-foot (4.6-meter) 

truss arms were attached to top of the pole. The pole weighed 536 pounds (243 kilograms), 

while the arms with simulated luminaire weighed 219 pounds (99 kilograms). The total weight 

of the luminaire pole system was 755 pounds (343 kilograms). In this test, the breakaway brass 

couplings (Version 3) fractured and allowed the aluminum pole system to rotate away from its 

initial ground attachment location. The remaining coupling stub heights were 13⁄4 inch (38 

millimeter), satisfying the 4-inch (100-millimeter) limit. Both the measured ΔVL and the 

extrapolated ΔVH satisfied the NCHRP Report No. 350 maximum allowable limit of 16.4 

feet/second (5.0 meters/second). Therefore, based on the results of tests BBC-5 and BBC-7, 

aluminum luminaire poles of nominal heights between 30 feet (9.1 meters) and 55 feet
3

(16.8 meters), with minimum wall thicknesses of 1⁄4-inch (6.4 millimeters), and weighs equal to 

or less than 755 pounds (343 kilograms) should be acceptable for use with the Version 3 

breakaway brass couplings.

For test no. BBC-6, the Version 3 brass couplings were used to support a 45-foot (13.7-meter)

nominal height, steel luminaire pole system. During the impact event, all four couplings 

fractured, leaving stub heights of 13⁄4-inch (38 millimeter). In the test, the pole system rotated 

away from its initial attachment location. The measured ΔVL was 13.25 feet/second (4.04 

meters/second), which satisfied the NCHRP Report No. 350 maximum allowable limit of 16.4 

feet/second (5.0 meters/second). However, the extrapolated ΔVH was calculated to be 16.85 

feet/second (5.14 meters/second). As a result, the 45-foot (13.7-meter) nominal height, steel

luminaire system did not meet the TL-3 evaluation criteria.

To identify the largest steel luminaire poles that can be used in combination with the breakaway 

brass couplings, further analysis was undertaken using the high-speed extrapolation equation to 

predict the ΔVH for different size poles. Steel luminaire pole configurations with varying 

thicknesses and heights were analyzed to determine the extrapolated high-speed, change in

longitudinal velocity (ΔVH). These extrapolated values were compared to the maximum

allowable limit of 16.4 feet/second (5.0 meters/second) in order to determine whether specific 

poles were acceptable for use with the brass couplings. During this study, the luminaire arms, 

base plate, and pole base diameter were held constant to the dimensions and weights

corresponding to those used in test no. BBC-6. Thus, only the shaft thickness and heights were 

altered. This analysis yielded the maximum shaft height for poles with a wall thickness ranging 

between 7 gauge (4.55 millimeter) and 11 gauge (3.03 millimeter). For a 7-gauge (4.55-

millimeter) wall thickness or the same thickness as used in test no. BBC-6, the maximum shaft 

height was determined to be 36 feet (11.0 m), with a nominal height of 41 feet (12.5 meters). The 

results from this analysis for all wall thicknesses are shown in the Table below.

Crash Testing

Pendulum testing was conducted on the test articles described above by the Midwest Roadside 

Safety Facility with their FHWA-approved Valmont/MwRSF-UNL pendulum. 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. 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 

The breakaway couplings proposed by the ILDOT and subsequently modified during your 

research effort were fabricated from ASTM B16, free-cutting brass, drilled and tapped for 1 inch

(25 millimeter) – 8UNC threaded bars, and had a circumferential notch cut around its outer 

surface to induce fracture. 

The final design (Version 3) as developed under your testing program for the Illinois DOT is 

shown as an enclosure to this letter and is acceptable for use on the NHS. The applicable 

luminaire pole systems for use with the Brass Breakaway Couplings when used to support 
4

aluminum or steel poles with maximum base diameters of 10 inches (254 millimeters) and within 

the height and weight ranges are shown in the following table.

Pole Type Thickness

Base

Diameter

Nominal

Height

System

Weight

Min. Max. Min. Max. Min. Max.

Aluminum ≥ 1⁄4 in.

(≥ 6.4 mm)

8 in.

(203 mm)

10 in.

(254 mm)

30 ft

(9.1 m)

55 ft

(16.8 m)

259 lb

(118 kg)

755 lb

(343 kg)

Steel

7 gauge

(4.55 mm) NA 10 in.(254 mm)

30 ft

(9.1 m)

41 ft

(12.5 m)

259 lb

(118 kg)

872 lb

(396 kg)

8 gauge

(4.18 mm) NA 10 in.(254 mm)

30 ft

(9.1 m)

46 ft

(14.0 m)

259 lb

(118 kg)

871 lb

(395 kg)

9 gauge

(3.80 mm) NA 10 in.(254 mm)

30 ft

(9.1 m)

51 ft

(15.5 m)

259 lb

(118 kg)

856 lb

(389 kg)

10 gauge

(3.42 mm) NA 10 in.(254 mm)

30 ft

(9.1 m)

59 ft

(18.0 m)

259 lb

(118 kg)

841 lb

(382 kg)

11 gauge

(3.03 mm) NA 10 in.(254 mm)

30 ft

(9.1 m)

60 ft

(18.3 m)

259 lb

(118 kg)

782 lb

(355 kg)

The final design of the brass coupling Version 3 may be used on the NHS in combination with 

any of the poles as indicated in this correspondence. As noted in your test report, poles with 

diameters larger than 10 inches (254 millimeters) must be analyzed independently using the 

proposed systems’ mass distribution and the extrapolation formula to calculate the high speed 

occupant impact velocities. Because the mast arms were held constant for all tests, any mass arm 

configurations other than truss-type luminaire arms also need to be analyzed on a case-by-case 

basis. 

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 letter provides an AASHTO/ARTBA/AGC Task Force 13 designator 

that should be used to create a new or updated Task Force 13 drawing.

• 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

Illinois DOT breakaway brass couplings 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.
5

• 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-73 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 Brass Couplings identified above are to be patented products and therefore are 

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

Director, Office of Safety Technologies 

Office of Safety

Enclosure