fHE 

1200 New Jersey Avenue. SE. 

US.Deportmcnl 

ononsportorion June 5, 2008 

Washington, DC 20590 

Federal Highway 

Administration 

ln Reply Refer To: HSSD/8-178 

Mr. Kevin K. Groeneweg 

Mobile Barriers LLC 

249 I 8 Genesee Trail Road 

Golden, CO 80401 

Dear Mr. Groeneweg: 

This leller is in response to your request for Federal Highway Administration (FHW A) 

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

Name of device: Mobile Barrier T!'ltiler 

Type of device: Portable Work Zone Barrier 

Test Level: NCHRP Repon 350 Test Level 2 (TL-2) or TL-3 

Testing conducted by: Southwest Research Institute 

Date of request: ApriJ 28, 2008 

Date.� of follow-up: May 28, 2008 and June 3. 2008. 

You requested that we find Lhis device acceptable for use on the NHS under the provisions of 

NationaJ Cooperative Highway Research Program (NCHRP) Repon 350 "Recommended 

Procedures for the Safety Performance Evaluation of Highway Features" and the proposed 

American Association of State Highway and Transponation Officials· Manual for Assessing 

Safely Hardware - 2008 (MASH-08). 

Requirements 

Roadside safety devices should meet the guidelines contained in the NCHRP Repon 350, 

"Recommended Procedures for the Safety Performance Evaluation of Highway Features". 

FHW A Memorandum "ACTION: Identifying Acceptable Highway Safety Features" of 

July 25, 1997, provides funher guidance on crash testing requirements of longitudinal barriers. 

You have also chosen lO anticipate the adoption of MASH-08, ao optioo that FHW' A has offered 

with the understanding that additional testing may need to be done if changes 10 the test criteria 

are made before MASH"08 is formalJy adopted. 

Description 

The Mobile Barrier Trailer (MBT) is an integrated, rigid wail, semi-trailer that is used in 

conjUJ1ction with standard semi-tractors LO provide mobile, improved. safety, and work 

environments for personnel at applicable maintenance, construction, and security sites. ll is an 

e,ctended, nrobile, longitudinal barrier that provides a physical and visual wall between passing 

:MERICAN--, 

ECONOMY (_,, 
2 

traffic and the maintenance and construction personnel. With an integrated crash attenuator at 

the rear, a semi-tractor at the front, and a rigid wall on the side toward passing traffic, the MBT 

wm provide approximately 30.5 m (100 ft) of barrier and protected work area. 

The basic trailer is comprised of two platforms and up to three wall sections. The platforms are 

each 6.4 m (21 ft) in overall length, 2.54 m (100 in) wide and 1.22 m (4 ft) high (riding 

approximately 1.52 m (5 ft) high with 305 mm (12 in) of ground clearance). The wall sections 

are each 6.10 m (20 ft) long, 610 mm (24 in) wide, and 1.22 m (4 ft) high (riding approximately 

1.52 m (5 ft) high with 305 mm (12 in) of ground clearance). A homogenous 6.4 mm (0.25 in) 

steel plate is welded to cover the outer side of each wall section. Each wall section abuts up 

against another of the platforms and is built the same to take an impact from either direction. 

There. are no snag points at the seams. The outer 6.4 mm (0.25 in) plate and associated welds are 

ground beveled to transition from one to the other. 

Dimensioned illustrations of the trailer are enclosed for reference as "Appendix A." 

Crash Testing 

One full-scale crash test was conducted using a 2329 kg Dodge, Ram quad cab pickup truck 

impacting at 23.5 degrees at 102.3 km/hr. The MBT deflected 0.61m (2 ft) during the jmpact. 

As seen in the enclosed test data summary sheet the evaluation criteria were within the limits 

specified in MASH-08. 

Findings 

Therefore, the-MBT described above and detailed in the enclosed dimensioned photographs is 

acceptable for use on the NHS under the range of condhions tested, when allowed by a highway 

agency. It will be acceptable for TL-2 or TL-3 usage depending on the test level of the Truck 

Mounted Attenuator that is affixed to the rear. 

You subsequently requested that FHW A accept the MASH-08 Test 3-11 as indicative of the 

NCHRP Report 350 acceptance as well. Because the nature of the MBT device and the impact 

performance of the MASH-08 pickup truck we can conclude that the MASH-08 Test 10 and the 

NCHRP Report 350 Tests 10 and 11 can be waived. (The MBT is a semi-rigid vertical wall with 

relatively low friction characteristics that can be favorably compared to vertical concrete barrier 

walls that passed prior full-scale testing). 

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

• This acceptance js limit�d to the crashwortruness characteristics of the devices and does not

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

Devices.

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

new acceptance letter.

• Should the FHW A 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, we reserve the right to modify

or revoke our acceptance.
3 

• 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 crashworthioess requirements of the FHWA and the 

NCHRP Report 350. 

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

B-178 and shall not be reproduced except in full. This letter and the test documentation 

upon which it is based are pt1blic information. All such letters and documentation may be 

reviewed at our office upon request. 

• The MBT is a patented product and considered proprietary. Ifproprietary devices are 

specified by a highway agency for use on Federal-aid projects, except exempt, non-NHS 

projects, they: (a) must be supplied through competitive bidding with equally sujtable 

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 ofroad for experimental purposes. Our regulations concerning 

proprietary products are contained in Title 23, Code of Federal Regulations, Section 

635.411. 

• This acceptance Jetter shall not be construed as authorization or consent by the FHW A to 

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

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

candidate device, and the 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 ofSafety 

Enclosures 
APPENDIX A 

Test Article 

(Contents of Appendix A submitted by Mobile Barriers ILC) 

A-1
Overview 

View as assembled with three wall sections 

\y -:.• ·~ ,# 

I .-

- , 

- r - - ~ ..,._ - ~ -------- - - .,,,(;., 

-~- . . . .:,.._ .:.'~~ -. 

Shortened configuration prepared for transport wlwall sections atop combined platforms. 

Overall trailer length (with 3 wall sections): 102' 

Overall length (with platforms only as shown ,above - oo wall sections installed): 42' 

Qengths· exclusive of tractor & T1'1A assembly, not shown) 

Width: 100" 

Approx Weight: 65,000 lbs with tractor and misc accompaniments 

B.teakdown: Platforms and rear axel assembly ("caboose") - 20,000 lbs 

Wall sections - 5,000 lbs (ea) 

Counterweight - 5,000 lbs per wall section 

Tractor and accompaniments - 20,000 lbs 

Clearance: 9-12" (+ / - 1 ") depending on configuration 

Height to top o f platforms (as taped): approx. 5' (58" with 12'' of clearance) 

Height to top of visual barrier (netting) or wall sections as stored above: approx 9' 

A-2 
Overview (cont) ... 

Length of platforms (2 shown attached): 21' ea 

("caboose" or rear axel assembly under platform opposite tractor) 

Length ofwall sections (2 shown facing/1 on opposite side): 20' ea. 

Configuration options: Platform and caboose with 0-3 wall sections 

Must be used with an NCHRP Report 350 compliant TMA that has been tested and accepted at TL-3 

or such other level as appropriate for applicable traffic speeds and deployment conditions 

(TMA not shown). 

A-3 
Dhnensions... 

Overall length with 3 wall sections: 102' 

2 Platforms (21' ea) 

1 2 

3 Wall sections (20' ea) 1 2 3 

A-4 
Dimensions (cont)... 

Trailer & Caboose (rear axel assembly) as seen from rear traffic side - wheel cover panel and 'IM.A. not 

shown. (license plate and splashguards blacked out) 

100" Width 

46" Wall/Platform height 

Caboose (rear axel assembly) 

9-12" Clearance 

A-5 
Wall construction ... 

Wall scctfons 

I, 2, 3 

Assembled 

Prcassembly as seen on end 

A-6

Top, mid, and lower 

beams with lower 

channel - 46" height 

(55-58" overal1 height 

w/ 9-12" clearance) 
42' 

Platform Construction ... 

__________ _,/ 

Platforms connected and loaded for transport, shown open from work side. 

Skeletal view. 

A-7
•• 

Table 4.1- Summary ofTest Results and Conditions -:a,I 

. ~:·~ 

... - - - ~ ..__ ,...,.

General Information 

Test Agency ........................ Southwest Research 1nstitute 

Test Number....................... MBT-1 

Test Date ............................. 04/03/2008 

Test Category ...................... 3-11 "Update" 

Test Article 

Type .................................... Longitudinal Barrier 

lnstalJ::ttio.n Length ............. 30.5 m (100 ft) 

Top-of-Barrier Height....... 1.52 m (5 ft) N 

\.,) Type of Primary Barrier .... Mobile longitudfoal barrier 0 

Hi Soil Test performed on concrete 

N Test Vehicle 

-..J Type .................................... 1⁄2Ton Quad Cab Pickup 

Designation ......................... 2270P 

Model ................................... 2002 Dodge Ram 1500 Quad Cab 

Mass (kg) ............................. 2329 

Jnertial Mass(kg) ................. 2329 

Dummy Mass (kg).............. 1A 

Gross Static Mass (kg) .......2329 

Impact Con ditions 

Speed (km/hr) ............ 102.3 

Angle (degrees) .......... 23.S 

Ex.it Conditions 

Speed (km/hr) ............ 80 (calculated) 

Angle (degrees) ...........0 

Occupant Risk Values 

Impact Velocity (m/s) 

x-direction ............ 4.0 

y-cLirection............-6.4 

Ridedown Accelerations (g's) 

x-direction ............ -7.9 

y-direction ............ 11.1 

Test Article Deflection 

Dynamic...................................... 0.61 m (2.0 ft) 

Static 9.5 cm (3.8 in) 

Vehicle D amage 

Exterior 

CDC .........................................1 l LFEWS 

VDS ...........................................11-LFQ-4 

I nterior 

OCDI .......................................... LP0000000 

Max. Deform. (mm) .................. 0 

Post ImpactVehicular Beh avior (llinited to events <1.000 seconds) 

Maximum Roll Angle (degrees) ....................... -7.8@0.107 sec. 

Maximum Pitch Angle (degrees) .................... 2.3 @ 0.447 sec. 

Maximum Yaw Angle (degrees) .....................29.3@ 0.374 sec. 

.-------------------t,~.J "' <227.~ ft:>------------------. 

9.1 ~ 30 ru 

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F.:i.tBos: