March 11, 2003


Mr. Rodney A. Boyd
Trinity Industries
2525 Stemmons Freeway
Dallas, Texas 75207

Dear Mr. Boyd:

In his February 28 letter to Mr. Richard Powers of my staff, your consultant, Mr. James Albritton, requested the Federal Highway Administration's acceptance of a design change to the TRACC impact attenuator.  This modification consists of substituting a modular base assembly for the original one-piece base assembly.  Dividing the base into three segments will facilitate repair work by not requiring removal of the entire unit for repair following minor impacts.  Anchorage and connection details for the new modular base are shown in the enclosures to this letter.

Staff members have reviewed these changes and agree that they are not likely to have any adverse impact on the crash performance of the TRACC.  Therefore, the modular base is acceptable for use with the TRACC on the National Highway System.

Sincerely yours,

(original signed by Michael S. Griffith)

Michael S. Griffith
Acting Director, Office of Safety Design
Office of Safety