400 Seventh St., S.W.

Washington, D.C. 20590

September 8, 2000

Refer to: HSA-1

Mr. Larry Leahy

Xcessories Squared 

P.O. Box 135 

Auburn, Illinois 62615

Dear Mr. Leahy:

Thank you for your May 5, 2000 letter requesting Federal Highway Administration (FHWA)

acceptance of your company’s perforated square steel tubes (PSST) as components of crashworthy

Type III barricades for use in work zones on the National Highway System (NHS). Type III

barricades framed with PSST have been successfully tested using a number of different base

connections. Your letter, plus an earlier letter dated March 27, 2000 requested acceptance of your

company’s base design which use PSST skids and a shear bolt connector to support the upright

elements. You requested that we find that base connection 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.”

Introduction

The FHWA guidance on crash testing of work zone traffic control devices is contained in two

memoranda. The first, dated July 25, 1997, titled “Information: Identifying Acceptable Highway

Safety Features,” established four categories of work zone devices: Category I devices were those

lightweight devices which could be self-certified by the vendor, Category II devices were other

lightweight devices which needed individual crash testing, Category III devices were barriers and other

fixed or massive devices also needing crash testing, and Category IV devices were trailer mounted

lighted signs, arrow panels, etc. The second guidance memorandum was issued on August 28, 1998,

and is titled “INFORMATION: Crash Tested Work Zone Traffic Control Devices.” This later

memorandum lists devices that are acceptable under Categories I, II, and III.

Testing

Type III barricades with frames of PSST have been tested in a number of studies. The table below lists

the FHWA letters of acceptance which include these barricades:
2

FHWA WZ-3

8-28-98

TTI for Texas

D.O.T.

TTI tested numerous work zone traffic control devices. All the devices listed

here were successfully tested in these two crash test programs and met TL-3

criteria. The crash testing is fully documented in the two reports1,2 which

should be consulted for additional details of the hardware.

Perforated Steel Tube Type III Barricade with Plastic Panels. Base connection

uses splice plates.

(see Figure 11.5 “Figure 41" & “Figure 45")

Perforated Steel Tube Type III Barricade with 1x8 Wood Panels. Base

connection uses splice plates.

(see Figure 11.6 “Figure 42")

Type III Perforated Tubing Barricade (3.7 m) Similar to barricades above

except for welded base connection.

(see Figure II.10 “Figure 2.") (Vertical braces added Acceptable with 1x8

wood or hollow core plastic rails.)

Type III perforated Tubing Barricade (1.2 m) Welded Base Connection. (see

Figure II.11 “Figure 3.") Acceptable with 1x8 wood or hollow core plastic

rails.

WZ-40

6-6-2000

FHWA / TTI Pooled-Fund Study Devices: Perf.Square Tube Type III with sign, 

WZ-44

7-25-2000

Penn Dot Type III Barricade / Sign Support. Perforated square tube frame, 4 ft. plastic

rails, plywood sign, warning light.

Your requests were that the PSST Type III barricade could be fabricated using any of the following

base connection details:

! PSST stub welded to the horizontal rails (or “skids”), also of PSST

! Using the rectangular splice plate and shear bolt arrangement used in the TTI tests described

in WZ-3, 

! Using the Xcessories Squared TBB-3 Trapezoidal Connector, shown in the enclosed

drawings (overall height of the TBB-3 is 5 1⁄2 inches). An important feature of this connector

is the use of two locking bubbles that fit in the holes of the PSST. This connection releases

when the barricade is struck allowing the barricade to fall flat. It also permits easy moving

and storage of the barricade when the bolts are loosened in the TBB-3 and the barricade can

lay flat.

Findings

The results of the crash testing of the various PSST Type III barricades met the FHWA requirements. 

We concur that the base connections listed above will result in acceptable performance when used on

any of the crash-tested PSST Type III barricades, therefore, they are acceptable for use as Test Level

3 devices on the NHS under the range of conditions tested, when proposed by a State.

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

! Our acceptance is limited to the crashworthiness characteristics of the devices and does not
3

cover their structural features, nor conformity with the Manual on Uniform Traffic Control

Devices (MUTCD).

! Any changes that may adversely influence the crashworthiness of the device will require a new

acceptance letter.

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

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

significantly different from the version that was crash tested, it reserves the right to modify or

revoke its 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 they will meet the crashworthiness requirements of FHWA and NCHRP Report 350. 

! To prevent misunderstanding by others, this letter of acceptance, designated as number WZ51, shall not be reproduced except in full. 

! Some of the barricade components may be patented products and considered "proprietary." 

The use of proprietary work zone traffic control devices in Federal-aid projects is generally of a

temporary nature. They are selected by the contractor for use as needed and removed upon

completion of the project. Under such conditions they can be presumed to meet requirement

"a" given below for the use of proprietary products on Federal-aid projects. On the other

hand, if proprietary devices are specified for use on Federal-aid projects, except exempt, nonNHS projects, they: (a) must be supplied through competitive bidding with equally suitable

unpatented items; (b) the highway agency must certify that they are essential for synchronization

with 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, a copy of which is enclosed. 

 Sincerely yours,

Frederick G. Wright, Jr.

Program Manager, Safety