January 13, 2004
Refer to: HSA-10/CC-54F
Mr. Rodney A. Boyd
2525 Stemmons Freeway
Dallas, Texas 75207
Dear Mr. Boyd:
In his December 11 letter to Mr. Richard Powers of my staff, your consultant Mr. James Albritton, requested Federal Highway Administration acceptance of specific design changes made to the original TRACC crash cushion. These changes were:
To confirm that these design changes did not adversely affect crash performance, crash tests were conducted at the Texas Transportation Institute (TTI) and described in that agency's January 2004 reports entitled "NCHRP Report 350 Test 3-31 of the Modified TRACC" and "NCHRP Report 350 Test 3-32 of the Modified TRACC." Since changes to the impact sled should have no measurable effect on side-impact performance, tests 3-31 and 3-32 were selected as being the most critical and were conducted. The summary results of these two certification tests are shown as enclosures 3 and 4.
Based on staff review of the design changes and certification test results, I consider the modified TRACC design as described above and shown in the enclosures acceptable for use on the NHS as a substitute for all previously-accepted TRACC designs, including the ShorTRACC, FasTRACC (test 3-31 only), and WideTRACC, at the same test levels at which they were previously accepted.
(original signed by John R. Baxter)
John R. Baxter, P.E.
Director, Office of Safety Design
Office of Safety