Title 23: Highways
PART 655—TRAFFIC OPERATIONS
Subpart F—Traffic Control Devices on Federal-Aid and Other Streets and Highways
Appendix to Subpart F of Part 655—Alternate Method of Determining the Color of Retroreflective Sign Materials and Pavement Marking Materials
1. Although the FHWA Color Tolerance Charts depreciate the use of spectrophotometers or accurate tristimulus colorimeters for measuring the daytime color of retroreflective materials, recent testing has determined that 0/45 or 45/0 spectroradiometers and tristimulus colorimeters have proved that the measurements can be considered reliable and may be used.
2. The daytime color of non-fluorescent retroreflective materials may be measured in accordance with ASTM Test Method E1349, “Standard Test Method for Reflectance Factor and Color by Spectrophotometry Using Bidirectional Geometry” or ASTM Test Method E 1347 (Replaces E97), “Standard Test Method for Color and Color-Difference Measurement by Tristimulus (Filter) Colorimetry.” The latter test method specified bidirectional geometry for the measurement of retroreflective materials. The geometric conditions to be used in both test methods are 0/45 or 45/0 circumferential illumination or viewing. Uniplanar geometry is not recommended for material types IV or higher (designated microprismatic). The CIE standard illuminant used in computing the colorimetric coordinates shall be D65 and the 2 Degree Standard CIE observer shall be used.
3. For fluorescent retroreflective materials ASTM E991 may be used to determine the chromaticity provided that the D65 illumination meets the requirements of E 991. This practice, however, allows only the total luminous factor to be measured. The fluorescent luminous factor must be determined using bispectral fluorescent colorimetry. Commercial instruments are available which allow such determination. Some testing laboratories are also equipped to perform these measurements.
4. For nighttime measurements CIE Standard Illuminant A shall be used in computing the colorimetric coordinates and the 2 Degree Standard CIE Observer shall be used.
5. Average performance sheeting is identified as Types I and II sheeting and high performance sheeting is identified as Type III. Super-high intensity sheeting is identified as Types V, VI, and VII in ASTM D 4956.
6. The following nine tables depict the 1931 CIE Chromaticity Diagram x and y coordinates for the corner points defining the recommended color boxes in the diagram and the daytime luminance factors for those colors. Lines drawn between these corner points specify the limits of the chromaticity allowed in the 1931 Chromaticity Diagram. Color coordinates of samples that lie within these lines are acceptable. For blue and green colors the spectrum locus is the defining limit between the corner points located on the spectrum locus:
Table 1 to Appendix to Part 655, Subpart F_Daytime Color Specification Limits for Retroreflective Material With CIE 2° Standard Observer and 45/0 (0/45) Geometry and CIE Standard Illuminant D65.---------------------------------------------------------------------------------------------------------------- Chromaticity Coordinates ---------------------------------------------------------------------------------- Color 1 2 3 4 ---------------------------------------------------------------------------------- x y x y y x x y----------------------------------------------------------------------------------------------------------------White........................ 0.303 0.300 0.368 0.366 0.340 0.393 0.274 0.329Red.......................... 0.648 0.351 0.735 0.265 0.629 0.281 0.565 0.346Orange....................... 0.558 0.352 0.636 0.364 0.570 0.429 0.506 0.404Brown........................ 0.430 0.340 0.430 0.390 0.518 0.434 0.570 0.382Yellow....................... 0.498 0.412 0.557 0.442 0.479 0.520 0.438 0.472Green........................ 0.026 0.399 0.166 0.364 0.286 0.446 0.207 0.771Blue......................... 0.078 0.171 0.150 0.220 0.210 0.160 0.137 0.038Light Blue................... 0.180 0.260 0.240 0.300 0.270 0.260 0.230 0.200Purple....................... 0.300 0.064 0.320 0.200 0.550 0.300 0.600 0.202----------------------------------------------------------------------------------------------------------------
Table 1a to Appendix to Part 655, Subpart F_Daytime Luminance Factors (%) for Retroreflective Material With CIE 2° Standard Observer and 45/0 (0/45) Geometry and CIE Standard Illuminant D65.---------------------------------------------------------------------------------------------------------------- Daytime Luminance Factor (Y %) by ASTM Type ----------------------------------------------------------------------------------- Color Types I, II, III and VI Types IV, VII, and VIII Type V ----------------------------------------------------------------------------------- Minimum Maximum Minimum Maximum Minimum Maximum----------------------------------------------------------------------------------------------------------------White....................... 27 ............ 40 ............ 15 ............Red......................... 2.5 12 3.0 15 2.5 11Orange...................... 14 30 12 30 7.0 25Brown....................... 4.0 9.0 1.0 6.0 1.0 9.0Yellow...................... 15 45 24 45 12 30Green....................... 3.0 9.0 3.0 12 2.5 11Blue........................ 1.0 10 1.0 10 1.0 10Light Blue.................. 12 40 18 40 8.0 25Purple...................... 2.0 10 2.0 10 2.0 10----------------------------------------------------------------------------------------------------------------
Table 2 to Appendix to Part 655, Subpart F_Nighttime Color Specification Limits for Retroreflective MaterialWith CIE 2° Standard Observer and Observation Angle of 0.33°, Entrance Angle of +5° and CIE Standard Illuminant A.---------------------------------------------------------------------------------------------------------------- Chromaticity Coordinates ----------------------------------------------------------------------------- Color 1 2 3 4 ----------------------------------------------------------------------------- x y x y x y x y----------------------------------------------------------------------------------------------------------------White............................. 0.475 0.452 0.360 0.415 0.392 0.370 0.515 0.409Red............................... 0.650 0.348 0.620 0.348 0.712 0.2550 0.735 0.265Orange............................ 0.595 0.405 0.565 0.405 0.613 0.355 0.643 0.355Brown............................. 0.595 0.405 0.540 0.405 0.570 0.365 0.643 0.355Yellow............................ 0.513 0.487 0.500 0.4700 0.545 0.425 0.572 0.425Green............................. 0.007 0.570 0.200 0.500 0.322 0.590 0.193 0.782Blue.............................. 0.033 0.370 0.180 0.370 0.230 0.240 0.091 0.133 -----------------------------------------------------------------------------Light Blue........................ Chromat icity coordin ates are yet to be determi ned. -----------------------------------------------------------------------------Purple............................ Chromat icity coordin ates are yet to be determi ned.----------------------------------------------------------------------------------------------------------------Note: Materials used as High-Conspicuity, Retroreflective Traffic Signage Materials shall meet the requirements for Daytime Color Specification Limits, Daytime Luminance Factors and Nighttime Color Specification Limits for Fluorescent Retroreflective Material, as described in Tables 3, 3a, and 4, throughout the service life of the sign.
Table 3 to Appendix to Part 655, Subpart F_Daytime Color Specification Limits for Fluorescent Retroreflective Material with CIE 2° Standard Observer and 45/0 (0/45) Geometry and CIE Standard Illuminant D65.---------------------------------------------------------------------------------------------------------------- Chromaticity Coordinates ------------------------------------------------------------------------------- Color 1 2 3 4 ------------------------------------------------------------------------------- x y x y x y x y----------------------------------------------------------------------------------------------------------------Fluorescent Orange.............. 0.583 0.416 0.535 0.400 0.595 0.351 0.645 0.355Fluorescent Yellow.............. 0.479 0.520 0.446 0.483 0.512 0.421 0.557 0.442Fluorescent Yellow-Green........ 0.387 0.610 0.369 .546 .428 .496 0.460 0.540Fluorescent Green............... 0.210 0.770 0.232 0.656 0.320 0.590 0.320 0.675Fluorescent Pink................ 0.450 0.270 0.590 0.350 0.644 0.290 0.536 0.230----------------------------------------------------------------------------------------------------------------
Table 3a to Appendix to Part 655, Subpart F_Daytime Luminance Factors (%) for Fluorescent Retroreflective Material With CIE 2° Standard Observer and 45/0 (0/45) Geometry and CIE Standard Illuminant D65.---------------------------------------------------------------------------------------------------------------- Luminance Factor Limits (Y) Color -------------------------------- Min Max YF*----------------------------------------------------------------------------------------------------------------Fluorescent Orange............................................................. 25 None 15Fluorescent Yellow............................................................. 45 None 20Fluorescent Yellow-Green....................................................... 60 None 20Fluorescent Green.............................................................. 20 30 12Fluorescent Pink............................................................... 25 None 15----------------------------------------------------------------------------------------------------------------*Fluorescence luminance factors (YF) are typical values, and are provided for quality assurance purposes only. YF shall not be used as a measure of performance during service.
Table 4 to Appendix to Part 655, Subpart F_Nighttime Color Specification Limits for Fluorescent RetroreflectiveMaterial With CIE 2° Standard Observer and Observation Angle of 0.33°, Entrance Angle of +5° and CIE Standard Illuminant A.---------------------------------------------------------------------------------------------------------------- Chromaticity Coordinates ------------------------------------------------------------------------------- Color 1 2 3 4 ------------------------------------------------------------------------------- x y x y x y x y----------------------------------------------------------------------------------------------------------------Fluorescent Orange.............. 0.625 0.375 0.589 0.376 0.636 0.330 0.669 0.331Fluorescent Yellow.............. 0.554 0.445 0.526 0.437 0.569 0.394 0.610 0.390Fluorescent Yellow-Green........ 0.480 0.520 0.473 0.490 0.523 0.440 0.550 0.449Fluorescent Green............... 0.007 0.570 0.200 0.500 0.322 0.590 0.193 0.782----------------------------------------------------------------------------------------------------------------
Table 5 to Appendix to Part 655, Subpart F_Daytime Color Specification Limits for Retroreflective Pavement Marking Material With CIE 2° Standard Observer and 45/0 (0/45) Geometry and CIE Standard Illuminant D65.---------------------------------------------------------------------------------------------------------------- Chromaticity Coordinates ------------------------------------------------------------------------------- Color 1 2 3 4 ------------------------------------------------------------------------------- x y x y x y x y----------------------------------------------------------------------------------------------------------------White........................... 0.355 0.355 0.305 0.305 0.285 0.325 0.335 0.375Yellow.......................... 0.560 0.440 0.490 0.510 0.420 0.440 0.460 0.400Red............................. 0.480 0.300 0.690 0.315 0.620 0.380 0.480 0.360Blue............................ 0.105 0.100 0.220 0.180 0.200 0.260 0.060 0.220----------------------------------------------------------------------------------------------------------------
Table 5a to Part 655, Subpart F_Daytime Luminance Factors (%) for Retroreflective Pavement Marking Material With CIE 2° Standard Observer and 45/0 (0/45) Geometry and CIE Standard Illuminant D65.------------------------------------------------------------------------ Luminance Factor (Y%) Color --------------------------- Minimum Maximum------------------------------------------------------------------------White....................................... 35Yellow...................................... 25Red......................................... 6 15Blue........................................ 5 14------------------------------------------------------------------------
Table 6 to Appendix to Part 655, Subpart F_Nightime Color Specification Limits for Retroreflective Pavement Marking Material With CIE 2° Standard Observer, Observation Angle of 1.05°, Entrance Angle of +88.76° and CIE Standard Illuminant A.---------------------------------------------------------------------------------------------------------------- Chromaticity Coordinates ------------------------------------------------------------------------------- Color 1 2 3 4 ------------------------------------------------------------------------------- x y x y x y x y----------------------------------------------------------------------------------------------------------------White........................... 0.480 0.410 0.430 0.380 0.405 0.405 0.455 0.435Yellow.......................... 0.575 0.425 0.508 0.415 0.473 0.453 0.510 0.490----------------------------------------------------------------------------------------------------------------Note: Luminance factors for retroreflective pavement marking materials are for materials as they are intended to be used. For paint products, that means inclusion of glass beads and/or other retroreflective components.
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[67 FR 49572, July 31, 2002, as amended at 67 FR 70163, Nov. 21, 2002; 68 FR 65582, 65583, Nov. 20, 2003]
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