Appendix B - Portable Changeable Message Sign Work Plan
National Transportation Product Evaluation Program
1. SCOPE
1.1 This project work plan covers the procedures used by the National Transportation Product Evaluation Program (NTPEP) to evaluate portable changeable message signs. The work plan includes sight tests, durability and reliability tests and a section describing the information provided by manufacturers to be included in the report after verification by the lead test state.
1.2 The NTPEP is a voluntary program whereby manufacturers may choose to have their products evaluated for a fee that is used primarily to cover the costs of the evaluation and producing its associated reports. The NTPEP reports the results of these evaluations, but does not accept or reject products. However, transportation officials may choose to use the results of the evaluations in the development and maintenance of an approved products list.
1.3 The NTPEP is a technical service program of the American Association of State Highway and Transportation Officials (AASHTO). This document and other documents produced by NTPEP may not be reproduced without the express written permission of AASHTO.
2. SIGHT TESTS
2.1Test Conditions - All Portable Changeable Message Signs submitted for testing shall meet the minimum requirements set forth in the Manual of Uniform Traffic Control Devices (MUTCD) and shall be positioned for all sight tests as described Part VI of the MUTCD. Conduct visibility, legibility and angularity tests using an evaluator with 20/20 corrected vision sitting in the driver's seat in a sedan-style vehicle. Perform all evaluations on a float road surface, in clear, cloudless weather in a setting free from outside visual influences (i.e. city lights, billboards, etc.). Four different persons will perform the evaluations by performing daytime and nighttime evaluations at ambient temperatures of 32 ± 5° F and 85 ± 5° F. The tests listed below will be conducted at both temperatures. Conduct all daytime evaluations with the sign facing either east or west. Brightness readings to be measured by a light meter. The changeable message sign shall be in automatic mode.
2.2Message Content - Use a non-traffic related message that uses the maximum number of lines available and between 75% to 80% of the available characters be illuminated. The message shall have three lines of characters. In all cases, ensure that single characters do not cover more than a single line. Record the message used and the character height. Change the content of the message for each test in the evaluation, and between evaluations.
2.3Visibility - Starting at a point 20 feet from the near edge of the sign in the direction parallel to the sign face and 2640 feet in from the front edge of the sign in the direction perpendicular to the sign face, determine whether or not the sign message is visible. The sign message is considered visible whenever the message portion is apparent, though not necessarily legible.