April 30, 2002 ** **

Refer to: HSA-10/CC73A

Barry D. Stephens, P.E.

Senior Vice President of Engineering

Energy Absorption Systems, Inc.

3617 Cincinnati Avenue

Rocklin, CA 95765

Dear Mr. Stephens:

In your April 5 letter, you requested the Federal Highway
Administration's review and acceptance of your REACT 350 (120\") and the
REACT 350 (96") Systems as meeting the National Cooperative Highway
Research Program (NCHRP) Report 350 evaluation criteria for Test Level 3
(TL-3) crash cushions. Your REACT 350 (60") has previously been tested
and accepted at this same test level. To support your new request, you
provided Mr. Richard Powers of my staff copies of your March 2002
engineering summary "REACT 350 (120\") (10 Foot \[3050 mm\] Wide System)
Qualification to NCHRP Report 350 Test Level 3" which included the March
2002 report by E-TECH Testing Services, Inc. entitled "NCHRP Report 350
Crash Test Results for the REACT 350 (120\") System," and a videotape
showing the full-scale tests that were conducted.

The TL-3 REACT 350 (120\") consists of an array of High Density
Polyethylene (HDPE) cylinders like those used with the REACT 350 (60").
Likewise, the internal struts, the monorail, and the monorail guides are
similar to those components in the 60" wide design. The space frame
diaphragms to which the cylinders are connected vary only in width from
the REACT 350 (60") diaphragms. The cylinders are arranged in thirteen
rows of two cylinders each, plus three nose cylinders, making the unit
9820-mm (32'-2") long. The nose cylinders are 36" in diameter and 32"
tall and each has a wall thickness of 0.878". The cylinders in rows 1-3
are 24" in diameter, have a wall thickness of 0.74 inches and are also
32 inches tall. The cylinders in rows 4-9 are the same thickness and
diameter but 40 inches high. Those in rows 10-13 are also 24" in
diameter and 40 inches high but their wall thickness increases to 1.14
inches. All cylinders in rows 4 through 13 have two-part (18 gauge and
14 gauge) steel "wheel deflectors" bolted to their outboard surfaces to
minimize the snagging potential in redirective hits. All cylinders in
rows 5-13 contain self-restoring, hinged internal steel struts to
provide redirection in side impacts. The two cylinders in each row are
attached to steel space frame diaphragms that slide along a steel
monorail similar to the monorail used with the QuadGuard family of
impact attenuators. Your specifications require the monorail to be
bolted to a 200 mm (8 inch) concrete foundation using 19 mm (0.75 inch)
diameter by 191 mm (7.5 inch) long ASTM A-193 Grade B7 polyester grouted
studs. Enclosure 1 is a schematic drawing of the tested unit.

Since the REACT 350 (120\") System is classified as a redirective,
non-gating crash cushion, the recommended NCHRP Report 350 test matrix
consists of eight tests. Four tests were run and successfully completed.
My staff agreed beforehand that both head-on tests (tests 3-30 and
3-31), test 3-36 (820-kg vehicle/100 km/h impact speed/15 degree impact
angle at the Critical Impact Point) and test 3-37 (2000-kg vehicle/100
km/h/20 degree impact at the same location) could be waived. Test 3-39,
the reverse direction impact, was waived because the rearmost corner of
the REACT 350 (120\") is effectively shielded by the concrete backup
structure and there are no external components on the cylinders that
might cause an impacting vehicle to snag. Tests actually conducted were
3-32, 3-33, a "modified" test 3-33 (essentially the same as test 3-36)
and test 3-38. All Report 350 evaluation criteria were met in each test.
Enclosure 2 contains summary information on the four tests that were
successfully conducted.

Based on staff review of the information you submitted, I agree that the
REACT 350 (120\") System, when attached to a 1525-mm (10 foot) wide
reinforced and anchored concrete backup, meets the appropriate
evaluation criteria for an NCHRP Report 350 TL-3 crash cushion and may
be used on the National Highway System (NHS) when selected by a
transportation agency. I also agree that the REACT 350 (96") may be
considered a TL-3 crash cushion without additional testing. This
determination is based on your statement that the only difference
between the 96" and 120" units is the width of the space frame
diaphragms, and on the results of the tests identified above plus
testing done previously on the REACT 350 (60"). Since the REACT 350
series of crash cushions remain proprietary devices, the use of any of
these designs on Federal-aid projects, except exempt, non-NHS projects,
is subject to the conditions listed in Title 23, Code of Federal
Regulations, Section 635.411.

Sincerely yours,

(original signed by A. George Ostensen)

A. George Ostensen

Program Manager, Safety

2 Enclosures