Federal Highway Administration
400 Seventh St., S.W.
July 25, 2007
In Reply Refer To: HSSD/CC-78D
Mr. Barry D. Stephens
Sr. Vice President Engineering
Energy Absorption Systems, Inc.
3617 Cincinnati Avenue
Rocklin, CA 95765
Dear Mr. Stephens:
Thank you for your May 8, 2007, letter requesting re-certification of the Federal Highway Administration’s (FHWA) acceptance of your company’s Safe-Stop® Trailer TMA as a test level 3 (TL-3) device for use on the National Highway System (NHS). Accompanying your letter was a report of crash testing conducted by E-Tech Testing Services, Inc. You requested that we continue to find this device acceptable for use on the NHS under the provisions of National Cooperative Highway Research Program (NCHRP) Report 350 “Recommended Procedures for the Safety Performance Evaluation of Highway Features.” The FHWA had initially ruled on the Safe-Stop® Trailer TMA on July 11, 2002, in FHWA acceptance letter CC-78 and supplemented with three additional letters.
The FHWA guidance on crash testing of roadside safety hardware is contained in a memorandum dated July 25, 1997, titled “INFORMATION: Identifying Acceptable Highway Safety Features.”
The FHWA acceptance of the Safe-Stop® Trailer TMA was based on successful completion of the “optional” NCHRP Report 350 tests 3-52 and 3-53 as agreed to by Mr. Richard Powers, then of our office. During a review by a neutral third party of the crash testing conducted on another manufacturer’s TMA Trailer we reached the conclusion that tests 3-52 and/or 3-53 may not be sufficient to verify that the trailer version of a TMA is crashworthy. At our meeting on April 20, 2007, we requested that EASI conduct test 3-51 on the Safe-Stop® Trailer TMA, as we were asking the manufacturer of the competing trailer to do the same. You complied, using a “blocked” shadow vehicle, and submitted the test report and videos for our review.
In your letter you also requested that the FHWA expand the acceptance of the Safe-Stop® Trailer TMA by acknowledging the successful results for a modified Test 3-51 and that this unit is capable of being used with an “infinite weight” support vehicle, can have a full-size flashing arrow panel (48” x 96”) installed without compromising impact performance, and fully passes the two standard as well as the two optional NCHRP 350 TL-3 TMA tests.
The flashing arrow panel was installed at the hitch end (tongue) of the unit to evaluate effects on impact performance as well as potential damage to the arrow panel itself. You also stated, and we agree, that all of the recommended NCHRP 350 evaluation criteria were successfully met. We noted that no additional hazards were created and the arrow panel was fully operational after, including operational lights and 90 degree tilting mechanism. In addition we recognized no damage occurred to the back end of the support vehicle or frame.
|Summary of NCHRP Report 350 Test 3-51|
|2000P Test Vehicle:||1988 Chevrolet Pickup|
|Vehicle Mass:||2000 kg Impact Speed: 99.0 km/hr|
|Shadow Vehicle:||1975 GMC 7500 Dump Truck|
|Shadow Vehicle Mass:||8550 kg, blocked against rigid wall|
|Occupant Impact:||9.6 m/s x-direction|
|Ridedown:||18.4 g’s x-direction|
Based upon your previous submittal and this new submittal, FHWA reconfirms that the Safe-Stop® Trailer TMA fully meets the TMA evaluation criteria in NCHRP Report 350 for Tests 3-50, 51, 52 and 53 at 100 km/h impact conditions. We also acknowledge that the Safe-Stop® Trailer TMA can be attached to heavy shadow vehicles weighing more than 9000 kg. Although the FHWA does not specifically endorse the use of arrow panels on trailer TMAs, we acknowledge that you successfully conducted a capacity test (3-51) and the arrow panel was not damaged and remained fully functional after the test.
Please note the following standard provisions that apply to FHWA letters of acceptance:
George (Ed) Rice, Jr.
Safety Home | FHWA Home | Feedback