September 18, 2002

HSA-10/B49C

Mr. Chad Heimbecker
Director, Product Development
Bryson Products, Inc.
224 Nazareth Pike, Suite 22
Bethlehem, PA 18020

Dear Mr. Heimbecker:

In your July 25 letter to Mr. Richard Powers of my staff, you requested formal acceptance of a revised plastic guardrail offset block named RE-BLOCK:IV and provided a copy of a Texas Transportation Institute report dated July 19, 2002, and entitled "Pendulum Testing and Evaluation of the Central Fabricator's Guardrail Blockout."

The RE-BLOCK:IV, as shown in the enclosure, is a hollow 4 inch x 8 inch block with three horizontal stabilizer bars and a depth of 14 inches for use with W-beam and 21-5/8 inches for use with Thrie-beam. Its material composition is similar to the original RE-BLOCK, using an average blend of 50 per cent HDPE and 50 per cent LDPE. Additionally, successful pendulum tests were conducted on a block made with 100 per cent HDPE and one made with 80 per cent HDPE and 20 per cent cross-linked HDPE/PP. All of these formulations include approximately 1 per cent carbon black to reduce the effects of UV degradation.

Based on staff review of the information you provided, the appropriate-sized RE-BLOCK:IV may be used with wood or steel strong-post W-beam and Thrie-beam guardrail systems on the National Highway System (NHS) when such use is acceptable to the contracting agency.

Please note the following provisions that apply to all FHWA letters of acceptance for synthetic offset blocks:

• Any changes that could adversely influence the impact resistance of the RE-BLOCK:IV may require a new acceptance letter.
  
  
• FHWA acceptance is based on the reported impact performance of the RE-BLOCK:IV and is not intended to address the durability of this product.
  
  
• Should the FHWA discover that the qualification testing was flawed, that in-service performance reveals unacceptable safety problems, or that the device being marketed is significantly different from the version that was originally approved, it reserves the right to modify or revoke its acceptance.
  
  
• You will be expected to certify to potential users that the material furnished has essentially the same chemistry, mechanical properties, and geometry as that submitted for acceptance,
  
  
• When proprietary products, such as the RE-BLOCK:IV, are specified for use on Federal-aid projects, except exempt, non-NHS projects, they: (a) must be supplied through competitive bidding (b) the highway agency must certify that they are essential for synchronization with 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.

Please contact Mr. Powers at (202) 366-1320 should you have questions.

Sincerely yours,

(original signed by Carol H. Jacoby)

Carol H. Jacoby, P.E.
Director, Office of Safety Design

Enclosure