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                        Hardware Eligibility Letters


            
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                Safety Eligibility Letter WZ-161
  
  **Hardware Type:**
            Work Zone Devices
                          **Code:**
            WZ-161
                          **Date:**
            10/24/2004
                          **Testing Criteria:**
            NCHRP 350
                          **Manufacturer:**
            FHWA memo
                          **Device Description:**
            Trailer Mounted Work Zone Devices (Category IV) and Grandfathering of older WZ devices (Category II)
                          **View PDF:**
            wz161.pdf (14.5 KB)
    
    
Category IV Work Zone Devices - Introduction
Our office memorandum “Crashworthy Work Zone Devices as of
October 1, 2000” (WZ-45) dated
September 13, 2000 ( http://safety.fhwa.dot.gov/roadway_dept/policy_guide/road_hardware/workzone/pdf/wz-45.pdf ),
postponed the decision date for trailer mounted work zone devices such as
changeable message signs, flashing arrow panels, portable traffic signals,
temporary work zone lighting, etc. The decision whether to require these
devices to be crash tested was extended to October 1, 2003, pending additional
study. That study, conducted for the
Federal Highway Administration using the Highway Safety Information System, has
been completed and shows no appreciable increase in the number of crashes into
these devices since the original study was completed in 1995.
Policy
The above leads us to extend our present policy of
encouraging, though not mandating, crashworthy installations. A determination of a requirement for crash
testing will be delayed until October 1, 2006. FHWA will continue to monitor
the in-service crash performance of Category IV devices and consider whether to
establish crash test requirements for devices in that category. If your state
has studied crashes of Category IV devices we would appreciate receiving a copy
or contact information. We will also encourage the design and testing of
crashworthy versions
In the interim, as should be done with these
devices even if proven crashworthy, they should be positioned and operated in
as safe a manner as practical. Category IV work zone devices should be
delineated or shielded.This would mean, where reasonable, placing them behind crashworthy barriers or shielding
them with a crash cushion.For devices that the highway agency or contractor
has decided are appropriate to operate unshielded within the clear zone, they
should be delineated with retroreflective channelizing devices as to be highly
visible, both in and out of service. They should be removed from the clear zone as soon as practicable after
they are no longer needed.
FHWA Division Offices
may wish to review their state DOT's policies and practices for dealing with
Category IV devices, and work with the state to improve compliance where
necessary. Guidelines for placing and delineating these work zone trailers may be found in MUTCD Sections 6F-52 and
6F-53, AASHTO Roadside Design Guide, Chapter 9, Section 9.4.2.4 and in the FHWA
Acceptance Letter WZ-45. The North Carolina DOT Policy for Use of Changeable Message Signs that we excerpted in
that WZ-45 memo may still be found on the Internet at: /sites/fhwa.dot.gov/files/hel/archive/preconstruct/traffic/congestion/docs/cmsopera.pdf
Industry activities
One manufacturer acted
upon our suggestion to develop crashworthy Category IV devices. Road Systems,
Inc., developed and crash tested a three-line changeable message sign meeting
NCHRP Report 350 Test Level 3 guidelines.
The crash testing of a conventional CMS and the redesigned, crashworthy
CMS may be seen on the Internet at http://www.roadsystems.com/tac.htm.
We encourage additional manufacturers to
redesign their devices to improve crashworthiness.
Grandfathering of older Work Zone devices
The August 28, 1998, memorandum between FHWA and AASHTO established October 1, 2000, as the deadline for Category II devices such as
portable sign stands, and Type I, II, and III barricades. Category II devices
for use on the NHS purchased after that date must be in compliance with NCHRP
Report 350 and FHWA crashworthiness guidelines. Untested devices already in
contractors' or states' inventory were to be allowed to remain in use until
"they complete their normal service life." FHWA did not set a deadline for removal of older, untested
devices, although many states did set their own deadline dates, mostly in 2002
or 2003.
At the September 2003
meeting of the AASHTO/AGC/ARTBA Joint Committee Task Force 13 - Standardization
of Highway and Bridge Hardware we heard an industry member's presentation on
the lengths to which some contractors or vendors are going to keep these older
devices in use. Major components of barricades and sign stands are being
replaced when damaged in order to keep the obsolete devices in use. FHWA
believes this violates the spirit of the FHWA/AASHTO agreement.
Work zone devices that
suffer major damage from a crash or construction site incident have reached the
end of their "normal service life."
A portable sign stand supporting an aluminum sign that is scratched or
dented to the extent that the sign blank needs to be refurbished is another
example of a device that has reached the end of its normal service life. If
your state has not set a "drop dead" date for removal of
non-crashworthy Category II work zone devices, or established inspection criteria
for determining when an older device has reached the end of its normal service
life, they should be encouraged to do so. Note that the MUTCD has established
January 17, 2005, as an implementation date for crashworthy work zone traffic
control devices (http://mutcd.fhwa.dot.gov/HTM/2003/intro/intro.htm )
on all highways. This would be a suitable "drop-dead" date for
obsolete devices on the NHS as well. U.S. DEPARTMENT OF TRANSPORTATION

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