U.S. Department 

Of Transportation 

Federal Highway 

Administration

400 Seventh St., S.W. 

Washington, D.C. 20590 

January 8, 1990 

Refer to: HNG-14/SS-17 

Mr. Arthur M. Dinitz 

President 

Transpo Industries, Inc. 

20 Jones Street 

New Rochelle, New York 10801-6024 

Dear Mr. Dinitz: 

This is in response to your October 13 letter to Mr. Thomas O. Willett requesting 

acceptance of your company’s Break-Safe breakaway sign support system for use on 

Federal-aid highway projects. Transmitted with your letter was the Southwest Research 

Institute report (dated September 1989) of the pendulum tests you had performed, and 

drawings of the Type A and Type B systems. Additional information including 

drawings, were submitted with your December 13, 1989, letter. 

The tests were conducted to assess the compliance of the Break-Safe frangible couplings 

with the breakaway requirements of the 1985 American Association of State Highway 

and Transportation Officials (AASHTO) Standard Specifications for Structural Supports 

for Highway Signs, Luminaires and Traffic Signals. These specifications have been 

adopted, with minor modifications by the Federal Highway Administration (FHWA). 

Testing was conducted using a 1,800 pound instrumented pendulum with a 10 stage 

crushable nose. The speed of the pendulum at impact was 20 m.p.h. (29.3 fps) in each 

case. The tests and their results are summarized below. Al impacts are head on except as 

noted for test TP-7. 

Test 

No. 

Test Article Description Total 

Weight 

(lbs) 

20 mph Test 

Velocity 

Change (fps) 

60 mph Calc 

Velocity 

Change (fps) 

Stub 

Height 

(in) 

TP-4 B-525 Coupling, W8x18 

Post 

297 4.1 4.9 0.3 

TP-5 B-650 Coupling, W12x35 

Post 

595 5.7 10.7 0.3 

TP-6 AI6 Coupling, W6x9 Post 98 1.6 4.1 0.3 

TP-7 B-525 Coupling, W8x18 

Post (45 degree hit) 

297 2.8 4.4 0.3 
TP-8 AUX8 Coupling, Back to 

Back Franklin Steel, 4 

pounds per foot U-post in 

“strong” soil 

110 2.3 2.4 4.0 

These results meet the change in velocity and stub height requirements adopted by the 

AASHTO and the FHWA. Therefore, except as limited below, your company’s BreakSafe Type A and Type B couplings are acceptable for use on Federal-aid highway 

projects, if proposed by a State. We note the AUX system using back to back U-posts 

was only tested in the strong (National Cooperative Highway Research Program 

(NCHRP) designation S-1) soil described in the NCHRP Report 230. Embedding the 

stub in “weak” (S-2) soil may allow the post and stub to rotate under impact, loading the 

couplings in a way that they do not readily fracture. Therefore, testing in “weak” soil is 

recommended to fully qualify the AUX Brake-Safe systems. Until the direct burial Type 

AUX systems are qualified in the S-2 soil, our acceptance is only extended for their use 

in “strong” soils. 

Additionally, we note that all the tests were run on single support installations with 

ballast attached to the upper portion of the support, but with no sign blank or upper hinge 

present. This is an unconventional and questionable test procedure. If the occupant risk 

test results were not so low we would request that tests be run on multiple support 

installations before accepting the use of the subject couplings in such installations. Your 

request that acceptance be granted for “any size or weight per foot provided the mass of 

the post under hinge mechanism is 600 pounds or less.” Since upper hinge/slip plate 

mechanisms were not involved in your tests, we are unable to confirm that such a mass 

would yield acceptable results. However, we believe that for installations where supports 

are further than 7 feet apart, posts up to 45 pounds per foot will perform satisfactorily (we 

have applied the same size limitation to slip-base sign supports). For dual support 

installations (where both the posts lie within a 7-foot path), we limit our acceptance to 

situations where the total weight of both posts below the hinges ifs 45 pounds per foot. 

The couplings should not be used in sign structures with three supports or more if posts 

are closer than 7 feet apart without further testing. 

Our acceptance is limited to he breakaway characteristics of the systems and does not 

cover their structural features. Presumably, you will supply potential users with 

sufficient information on structural design and installation requirements to ensure proper 

performance. We anticipate that the States will require certification from Transpo 

Industries that the hardware furnished has essentially the same chemistry, mechanical 

properties, and geometry as those used in the tests, and that they will meet the FHWA 

breakaway requirements. 

Since the Break-Safe couplings are proprietary items, to be used in a Federal-aid highway 

project they: (a) must be supplied through competitive bidding with equally suitable 

unpatented items; (b) the State highway agency must certify that they are essential for 

synchronization with existing highway facilities or that no equally suitable alternate 

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, a copy of which is enclosed. 

 Sincerely yours, 

 L. A. Staron, Chief 

 Federal-Aid and Design Division 

Enclosures