1200 New Jersey Ave., SE 

 Washington, D.C. 20590 

September 9, 2009 

In Reply Refer To: 

 HSSD/B-196 

Mr. Geoff Maus 

Chief Design Engineer 

TrafFix Devices, Inc. 

160 Avenida La Pata 

San Clemente, CA 92673 

Dear Mr. Maus: 

 

This letter is in response to your request for the Federal Highway Administration (FHWA) 

acceptance of a roadside safety system for use on the National Highway System (NHS). 

 Name of system: TrafFix Devices, Inc., Sentry Water-Cable Barrier 

 Type of system: Water filled barrier 

 Test Level: NCHRP Report 350 TL-1, TL-2 and TL-3 

 Testing conducted by: Karco Engineering, LLC 

 Date of request: January 21, 2009 

 Date of completed package: July 27, 2009 

 Request initially acknowledged: January 26, 2009 

You requested that we find this system acceptable for use on NHS under the provisions of the 

National Cooperative Highway Research Program (NCHRP) Report 350 “Recommended 

Procedures for the Safety Performance Evaluation of Highway Features.” 

 

Requirements 

Roadside safety systems should meet the guidelines contained in the NCHRP Report 350. The 

FHWA Memorandum “ACTION: Identifying Acceptable Highway Safety Features” of July 25, 

1997, provides further guidance on crash testing requirements of longitudinal barriers. 

Description 

The TrafFix Devices, Inc., Sentry Water-Cable Barrier was designed without the need for an 

external attached structure to meet Test Level 2 (TL-2) and TL-3 barrier performance. A second 

design objective was to produce a product with minimal lateral deflection of the barrier. Each 

section is a freestanding longitudinal wall unit with an approximate width, height, and length of 

25 inches by 46 inches by 84 inches (635 mm x 1092 mm x 2032 mm) respectively. 

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Each section has 11 connecting lugs, 5 on one end, and 6 on the opposite end. The four upper 

lugs on each barrier section contain one each independent corrosion resistant steel wire rope 

molded into the Sentry Water-Cable Barrier. The four wire rope pieces in each section act 

similarly to a cable barrier when impacted. A 1.25-inch (31.8-mm) diameter steel 

T-pin drops through the 1.5-inch (38.1-mm) diameter holes in the lugs, linking the sections 

together. The shell of each section is made up of high density polyethylene (HDPE). 

Water-Cable Barrier wall sections are set in position, connected by the T-pin and T-pin clip, and 

filled with water. The empty weight of each Water-Cable Barrier section is approximately 

165 pounds (75 kg). The weight of each Water-Cable Barrier section when filled with water is 

approximately 2,150 pounds (975 kg). The TrafFix Devices, Inc., Sentry Water-Cable Barrier 

does not use an external structure to achieve TL-2 or TL3 barrier performance, reducing the 

chance of improper assembly of the barrier. 

Crash Testing 

Three full scale crash tests were performed on a series of 25 linked Water Wall sections. The 

Water Wall sections were filled with water; no sections were anchored to the ground. The 

impact point was the center of the thirteenth barrier section from the beginning of the series. The 

25 linked Sentry Water-Cable Barrier sections provided a tested length of approximately 158 feet 

(48 m). The Water-Cable Barrier system length and impact point were chosen to replicate 

previous tests performed on products of this category. The impact point at the center of the 

Water-Cable Barrier was also deemed to be “worst case”, as it is the mid point between the 

supported ends. The test data summary sheets for the three tests, NCHRP Report 350 Test 2-11, 

3-10, and 3-11 are enclosed for reference. In each case the vehicle was captured by the barrier 

system with the vehicle experiencing substantial pitching and yawing. However, the vehicle 

remained upright in contact with the barrier and did not rebound into adjacent lanes. All 

occupant risk values were within allowable limits. The design deflection distance, as recorded in 

Test 3-11, was 9 feet (2.74 m). 

Findings 

You requested the following FHWA Acceptance conditions for the Sentry Water-Cable Barrier:

Request #1: Longitudinal Barrier at Test Levels TL-3, TL-2, and TL-1 

Request #2: Longitudinal Channelizing Device at Test Levels TL-3, TL-2 and TL-1. 

We concur that the system described above and detailed in the enclosed drawings is acceptable 

for use on the NHS above as a barrier and a longitudinal channelizing device under the range of 

conditions tested and as expanded in Requests #1 and #2, when such use is acceptable to a 

highway agency. TL-1 performance is assumed based on the successful TL-2 and TL-3 testing. 

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

 This acceptance is limited to the crashworthiness characteristics of the systems and does 

not cover their structural features, nor conformity with the Manual on Uniform Traffic 

Control Devices. 

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 Any changes that may adversely influence the crashworthiness of the system will require 

a new acceptance letter. 

 Should FHWA discover that the qualification testing was flawed, that in-service 

performance reveals unacceptable safety problems, or that the system being marketed is 

significantly different from the version that was crash tested, we reserve the right to 

modify or revoke our acceptance. 

 You will be expected to supply potential users with sufficient information on design and 

installation requirements to ensure proper performance. 

 You will be expected to certify to potential users that the hardware furnished has 

essentially the same chemistry, mechanical properties, and geometry as that submitted for 

acceptance, and that it will meet the crashworthiness requirements of FHWA and 

NCHRP Report 350. 

 To prevent misunderstanding by others, this letter of acceptance is designated as number 

B-196 and shall not be reproduced except in full. This letter and the test documentation 

upon which it is based are public information. All such letters and documentation may be 

reviewed at our office upon request. 

 Because some water ballasted barriers and channelizers are similar in appearance, FHWA 

recommends labeling each unit or module to indicate limitations on use. When used as a 

barrier all hardware, both internal and external that was used in the crash testing, shall be 

installed per the manufacturer’s instructions. Recommended guidance for such labels 

may be found on the Web site of the AASHTO/AGC/ARTBA Task Force 13 at 

http://www.aashtotf13.org. 

 The TrafFix Devices, Inc., Sentry Water-Cable Barrier is a patented product and 

considered proprietary. If proprietary systems are specified by a highway agency for use 

on Federal-aid projects, except exempt, non-NHS projects, (a) they must be supplied 

through competitive bidding with equally suitable unpatented items; (b) the highway 

agency must certify that they are essential for synchronization with the existing highway 

facilities or that no equally suitable alternative exists; or (c) they must be used for 

research or for a distinctive type of construction on relatively short sections of road for 

experimental purposes. Our regulations concerning proprietary products are contained in 

Title 23, Code of Federal Regulations, Section 635.411. 

 This acceptance letter shall not be construed as authorization or consent by FHWA to 

use, manufacture, or sell any patented system for which the applicant is not the patent 

holder. The acceptance letter is limited to the crashworthiness characteristics of the 

candidate system, and FHWA is neither prepared nor required to become involved in 

issues concerning patent law. Patent issues, if any, are to be resolved by the applicant. 

Sincerely yours, 

 

David A. Nicol, P.E. 

Director, Office of Safety Design 

Office of Safety 

Enclosures 

FHWA:HSSD:NArtimovich:tb:61331:9/3/09 

File: s://directory folder/nartimovich/B196_TrafFix_WaterWall_v2.doc 

cc: HSSD (Reader, HSA; Chron File, HSSD; NArtimovich, HSSD; 

 WLongstreet, HSSD; MMcDonough, HSSD) 

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