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FHWA Home / Safety / Roadway Departure / Safety Eligibility Letter

Safety Eligibility Letter CC-110

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U.S. Department of Transportation
Federal Highway Administration

1200 New Jersey Ave. S.E.
Washington, D.C. 20590

November 16, 2010

In Reply Refer To: HSSI/CC-110

Mr. Barry D. Stephens, P.E.
Sr. Vice President Engineering
Energy Absorption Systems, Inc.
3617 Cincinnati Avenue
Rocklin, CA 95678

Dear Mr. Stephens:

This letter is in response to your request for the Federal Highway Administration (FHWA) acceptance of a roadside safety device for use on the National Highway System (NHS) under the provisions of the National Cooperative Highway Research Program (NCHRP) Report 350 testing guidelines.

Name of device: Test Level (TL-2) ACZ 350™ System
Type of device: Impact Attenuator and Transitions
Test Level: NCHRP Report 350 TL-2
Testing conducted by: E-Tech Testing Services, Inc.
Date of request: July 15, 2010
Task Force 13 Designator: SCI24

Decision:
The following device was found acceptable, with details provided below:
• ACZ 350 System meeting TL-2 conditions for a Report 350 non-redirective, gating crash cushion where impact speeds are not expected to exceed 70 km/h (44 mph).

Requirements
Roadside safety devices should meet the guidelines contained in NCHRP Report 350. The FHWA Memorandum “ACTION: Identifying Acceptable Highway Safety Features” of July 24, 1997, provides further guidance on crash testing requirements of longitudinal barriers.

Description
As per the submitted crash test report, the ACZ-350 System is designed to perform as a narrow, non-redirecting, gating crash cushion to shield the blunt ends of both permanent and variable length portable concrete median barriers (P/CMB), as well as steel barrier such as the Vulcan Barrier. The TL-3 ACZ 350 System was accepted by the FHWA on February 13, 2009, (reference HSSD/CC-47D). The 2-segment ACZ 350™ System consists of a sheet metal nose, two water-filled barrier segments, and a steel transition pinned together to act as an end treatment.

The nose is constructed of light gauge steel and connects directly to the front-most water filled barrier segment. Each of the two water filled barrier segments is equipped with an external top-mounted steel stiffener which is rigidly fixed to each respective segment and an internal steel frame as well as external side-mounted steel laminated straps. A heavy duty non-crushable steel transition completes the system by connecting the last water filled segment to the blunt end of the downstream barrier, be it P/CMB or Vulcan Barrier. The ACZ 350™ System has an overall length of 5.6 meters (18 feet, 4inches). The overall height is 815 mm (32 inches).

Crash Testing
As per the submitted crash test report, the following physical crash testing was conducted:

  1. Test 2-40 (820C/ 70kph/ 0 degree/ w/4 offset): Impact speed = 70.3 km/h, ridedown = −9.6 g’s, Longitudinal ΔV = 10.2 m/s.
  2. Test 2-41 (2000P/ 70kph/ 0 degree): Impact speed = 71.3 km/h, ridedown = −8.6 g’s, Longitudinal ΔV = 9.2 m/s.

The crash test summaries are enclosed for reference. In addition, the following tests are requested to be waived as per the following comparisons:

Test Number Test Level Requested Comparison
1-40 TL1 Not necessary since Test 2-40 passed
1-41 TL1 Not necessary since Test 2-41 passed
1-42 TL1 Not necessary since Test 2-40 is worst case
1-43 TL1 Not necessary since Test 2-41 is worst case
1-44 TL1 Not necessary since this test is similar to the previous successful Test 3-44 as per Acceptance Letter CC-47D.
2-42 TL2 Not necessary as Test 2-40 (see above) is worst case
2-43 TL2 Not necessary as Test 2-41 (see above) is worst case
2-44 TL2 Not necessary since this test is similar to the previous successful Test 3-44 as per Acceptance Letter CC-47D.

Findings
The FHWA concurs to the submitted physical crash testing and to requested comparisons relating to the proposed TL-2 2-segment ACZ 350™ System only. Therefore, the ACZ 350 Crash Cushion System meets the TL-2 impact conditions and evaluation criteria for a Report 350 non-redirective, gating crash cushion and is acceptable for use on the NHS. However, it is critical this system be used only when such use is acceptable to the contracting authority and only in locations where impact speeds are not expected to exceed 70 km/h (44 mph). Regarding the TL-l 1-segment ACZ-350™ System, the submitted crash test report did not address this particular system. Therefore, FHWA does not concur with the requested comparisons relating to the proposed 1-segment ACZ 350™ System. Additional physical crash testing on the proposed 1-segment ACZ 350™ System is strongly recommended.

Please note the following standard provisions that apply to the FHWA letters of acceptance:

 

Sincerely yours,

/* Signature of Michael S. Griffith */
Michael S. Griffith
Director, Office of Safety Technologies
Office of Safety

2 Enclosures

Page last modified on January 17, 2013.
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