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                Safety Eligibility Letter WZ-267
  
  **Hardware Type:**
            Work Zone Devices
                          **Code:**
            WZ-267
                          **Date:**
            02/08/2008
                          **Testing Criteria:**
            NCHRP 350
                          **Manufacturer:**
            Horizon Signal Technologies
                          **Device Description:**
            Portable Traffic Signal System
                          **View PDF:**
            wz267.pdf (815.42 KB)
    
    
Skip to contentSkip to contentUnited States Department of Transportation - Federal Highway AdministrationDOT logo
U.S. Department of Transportation
**Federal Highway Administration**
1200 New Jersey Ave. S.E.
Washington, D.C. 20590February 8, 2008
**In Reply Refer To: HSSD/WZ-267**
Mr. David  Krahulec
Vice President/Chief Operating Officer
Horizon Signal Technologies, Inc.
216 Line Road
Malvern,   PA 19355

Dear  Mr. Krahulec:
In your January 2, 2008, letter you requested the Federal  Highway Administration’s (FHWA) acceptance of your company’s SQ2 pedestal mount  portable traffic signal system as a crashworthy traffic control device for use  in work zones on the National Highway System (NHS). Accompanying your letter was a crash test  report prepared by Transportation Research Center Inc., videos of the crash  test conducted, and a drawing of the SQ2 system. You requested that we find this device  acceptable for use on the NHS under the provisions of the National Cooperative  Highway Research Program (NCHRP) Report 350 “Recommended Procedures for the  Safety Performance Evaluation of Highway Features.”
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.
The SQ2 pedestal mount portable traffic signal system consists of three signal lights mounted on a retractable, manually operated  boom, powered by two 12-volt batteries.  The signal heads are cast aluminum and have three 12-inch (30.5 cm)  diameter LED signal lamps. The signal  heads are equipped with visors that extend a minimum of 10 inches (25.4 cm)  beyond the signal head. The total mass  of the system is approximately 385.8 pounds (175 kg). The overall extended height of each SQ2  system is 11.33 feet (3.45 m) and its width is 27.5 inches (0.70 m). A  detailed drawing of the SQ2 pedestal mount portable traffic signal system is  enclosed.
In coordination with the FHWA you conducted a crash test  (Test 3-71) to verify the impact performance of your device at an impact speed  of 62 mph (99.8 km/h) using a 820C passenger car test vehicle. The crash test set up was such that the test  vehicle impacted a pair of the SQ2 signal systems simultaneously. One of the signal systems was oriented with  the signal head facing the test vehicle and another signal system was rotated  90 degrees with the signal head facing the first signal system. The FHWA recommended test setup protocol  typically requires that the second device be rotated or oriented 90 degrees  from the first system and placed 20 feet (6.1 m) downstream from the first  device. The test set up protocol  concerning downstream placementwas outside the recommendations but the  FHWA does accept the results of the test as conducted and will not require a  retest.
During the test, the vehicle bumper contacted the two signal  systems simultaneously. Upon impact, the  signal system supports rotated and both signal heads fully impacted the  roof. The vehicle remained upright and  maximum displacement of the signal systems was 273.3 feet 
  (83.3 m) measured longitudinally from the point of  impact. The maximum occupant compartment  deformation was 2.67 inches (67 mm) at the passenger side of the roof. The maximum occupant impact velocity was  16.78 mph (7.5 m/s) and the maximum occupant ridedown acceleration was 2.9  g’s.
In summary, the SQ2  pedestal mount portable traffic signal system, as described above, meets the appropriate evaluation criteria for NCHRP  350 Test Level 3 work zone traffic control devices and may be used at all  appropriate locations on the NHS when selected by the contracting authority. This device  is accepted by the FHWA for use under the range of conditions tested and is  considered crashworthy when deployed at the fully extended height of 11.33  feet (3.45 m).
Please note the following standard provisions that apply to  the FHWA letters of acceptance:
This acceptance is limited to the  crashworthiness 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 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 the FHWA and the NCHRP  Report 350.
  To prevent misunderstanding by others, this  letter of acceptance, designated as number WZ-267, shall not be reproduced  except in full. This letter, and the  test documentation upon which this letter is based, is public information. All such letters and documentation may be  reviewed at our office upon request.
  The SQ2 pedestal mount portable traffic signal  system is a patented product and  considered proprietary. If proprietary  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 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 the FHWA 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 of the 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
David A.  Nicol    
Director,  Office of Safety Design
Office of  SafetyEnclosures
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