National Transportation Product Evaluation Program (NTPEP) Evaluation of Arrowboards and Portable Changeable Message Signs

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  • Introduction and Background

    AASHTO representatives to the NTPEP subcommittee voted in 1997 to establish a Work Panel Task Force to develop a draft work plan for the evaluation of Flashing Arrow Panels (Arrowboards) and Portable Changeable Message Signs (PCMS). This task force met in Washington, DC in April, 1998 to discuss and draft a work plan that was presented at the 1998 NTPEP annual conference held in Nashville, TN. Members included the NTPEP Coordinator, Mark Alderman, (VA, Chairman), Jim Kellenberger, (NC), Teresa Lewandowski, (DE), Edward Paulis (MD), Doug Tomlinson (PA). Input for this draft work plan was gathered from specifications and general comments submitted from the AASHTO members. Many of the remaining agency specifications were located on web-sites or through other research. The final work plan (see Appendix A & Appendix B ), with revisions from the NTPEP Oversight Committee, was adopted in November 1998. While this final work plan is printed as one work plan there are actually two work plans contained in the document, one for Arrowboards and one for PCMS.

    The NTPEP Coordinator made this work plan available to Industry at-large through the American Traffic Safety Services Association (ATSSA) and solicited vendor interest for Arrowboard and PCMS testing in December of 1998. Arrowboards and PCMS were provided to NCDOT in January, 1999 with the winter tests held in February and April of 1999 and the summer tests held in July and August of 1999. Many logistical and technical obstacles had to be overcome in implementing the work plan for the first time which are discussed in the Data Charts section of this report. All Arrowboards and PCMS tested during the Winter and Summer 1999 cycle were solar powered.

    The sight tests described in Section 2 of the work plan for Arrowboards and PCMS were performed in Wilson, NC at the Wilson Industrial Airport (see Appendix C for location specifics). Test sections 3 and 4 of the work plan for Arrowboards and PCMS were performed in Raleigh, NC at the NCDOT Equipment Depot.

    Every effort has been made in this document to provide an accurate reflection of information discovered during the implementation of this work plan for Arrowboards and PCMS. This information should be very useful for making purchase decisions. A CD-ROM has been included to allow query and reporting of the data easier for the NTPEP user.

    As a State that strongly supports the NTPEP program, it is believed that the information contained in this report will be useful in making decisions about what products or types of products best suit the purchaser’s needs. While it is never recommended to buy any device prior to an inspection of the device, it is believed extended testing by individual agencies can be eliminated by using the information contained in this report. If an agency has any specific questions about the data in this report please feel free to contact Steve Kite at 919-662-4339.​

  • Work Plan

    The brightness readings required in the Sight test (2.1) for the Arrowboard and PCMS work plans were taken with an AEMC model 814 light meter. The light meter was placed against the lens or the lens cover of the Arrowboard and PCMS to get the light meter as close to the light source as possible. The same light meter was used in the Durability test (3.3) for both devices. Appendix E shows the position of the light while taking the readings for PCMS and Arrowboards.
     
    No area with close proximity to Raleigh could be found to meet the requirements of Table 1 in the Visibility test (2.3) of the Arrowboard work plan for Type "C" arrowboards. The team recorded the distance at which the arrowboards were visible and believe that all arrowboards tested in this test cycle exceeded the Manual on Uniform Traffic Control Devices requirement of 1 mile.
     
    The Angularity test (2.5) for both devices was performed using field engineering judgement. No surveying instruments were used to determine this angle as they were not practical in this application.
     
    The Sight tests (2.3, 2.4, 2.5) for both the Arrowboards and PCMS were performed with all the devices in the test cycle placed side by side a minimum of 20 feet apart at the east end of Runway 9-27 (see Appendix C ). All three tests for Arrowboards and PCMS were performed using a 1998 Plymouth Breeze sedan in good condition. While the Angularity tests (2.5) were performed from the drivers seat by all four evaluators, the Visibility tests (2.3) and the Legibility tests (2.4) were performed with all the evaluators seated in the vehicle at once as each sign was reviewed. This was done for tests 2.3 and 2.4 because of the time consuming nature of these tests. Some thin high clouds were present during the sight tests.
     
    As stated earlier, the work plan was developed by a task force which reviewed a large number of member agency specifications. Several State Highway Agencies require solar-powered Arrowboards and PCMS to run with their solar panels disconnected from the batteries they replenish. It was decided by the task force to create test 3.2.2 in the work plan to measure this reliability feature of the devices. In several cases this required breaking solder joints to disconnect the battery banks from the power source. It became obvious to the testing team that accidental solar power disconnect had become a problem in the day to day operation of the devices and many manufacturers had dealt with that in a very positive way by making it difficult or impossible to accidentally disconnect the power source.​
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