Appendix to - 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 ten 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.

Color Chromaticity Coordinates 1 2 3 4 x y x y y x x y White0.3030.3000.3680.3660.3400.3930.2740.329 Red0.6480.3510.7350.2650.6290.2810.5650.346 Orange0.5580.3520.6360.3640.5700.4290.5060.404 Brown0.4300.3400.4300.3900.5180.4340.5700.382 Yellow0.4980.4120.5570.4420.4790.5200.4380.472 Green0.0260.3990.1660.3640.2860.4460.2070.771 Blue0.0780.1710.1500.2200.2100.1600.1370.038 Light Blue0.1800.2600.2400.3000.2700.2600.2300.200 Purple0.3020.0640.3100.2100.3800.2550.4680.140

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.

Color Daytime Luminance Factor (Y %) by ASTM Type Types I, II, III and VI Types IV, VII, and VIII Type V Minimum Maximum Minimum Maximum Minimum Maximum White274015Red2.5123.0152.511 Orange143012307.025 Brown4.09.01.06.01.09.0 Yellow154524451230 Green3.09.03.0122.511 Blue1.0101.0101.010 Light Blue124018408.025 Purple2.0102.0102.010

Table 2 to Appendix to Part 655, Subpart F—Nighttime Color Specification Limits for Retroreflective Material With CIE 2° Standard Observer and Observation Angle of 0.33°, Entrance Angle of + 5° and CIE Standard Illuminant A.

Color Chromaticity Coordinates 1 2 3 4 xyxyxyxyWhite0.4750.4520.3600.4150.3920.3700.5150.409 Red0.6500.3480.6200.3480.7120.25500.7350.265 Orange0.5950.4050.5650.4050.6130.3550.6430.355 Brown0.5950.4050.5400.4050.5700.3650.6430.355 Yellow0.5130.4870.5000.47000.5450.4250.5720.425 Green0.0070.5700.2000.5000.3220.5900.1930.782 Blue0.0330.3700.1800.3700.2300.2400.0910.133 Purple0.3550.0880.3850.2880.5000.3500.6350.221 Light BlueChromaticity coordinates are yet to be determined.

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.

Color Chromaticity Coordinates 1 2 3 4 x y x y x y x y Fluorescent Orange0.5830.4160.5350.4000.5950.3510.6450.355 Fluorescent Yellow0.4790.5200.4460.4830.5120.4210.5570.442 Fluorescent Yellow-Green0.3870.6100.369.546.428.4960.4600.540 Fluorescent Green0.2100.7700.2320.6560.3200.5900.3200.675 Fluorescent Pink0.4500.2700.5900.3500.6440.2900.5360.230 Fluorescent Red0.6660.3340.6130.3330.6710.2759.7350.265

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.

Color Luminance Factor Limits (Y) Min Max YF* Fluorescent Orange25None15 Fluorescent Yellow45None20 Fluorescent Yellow-Green60None20 Fluorescent Green203012 Fluorescent Pink25None15 Fluorescent Red203015

*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 Retroreflective Material With CIE 2° Standard Observer and Observation Angle of 0.33°, Entrance Angle of + 5° and CIE Standard Illuminant A.

Color Chromaticity Coordinates 1 2 3 4 x y x y x y x y Fluorescent Orange0.6250.3750.5890.3760.6360.3300.6690.331 Fluorescent Yellow0.5540.4450.5260.4370.5690.3940.6100.390 Fluorescent Yellow-Green0.4800.5200.4730.4900.5230.4400.5500.449 Fluorescent Green0.0070.5700.2000.5000.3220.5900.1930.782 Fluorescent Red0.6800.3200.6450.3200.7120.2530.7350.265

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.

Color Chromaticity Coordinates 1 2 3 4 x y x y x y x y White0.3550.3550.3050.3050.2850.3250.3350.375 Yellow0.5600.4400.4900.5100.4200.4400.4600.400 Red0.4800.3000.6900.3150.6200.3800.4800.360 Blue0.1050.1000.2200.1800.2000.2600.0600.220 Purple0.3000.0640.3090.2600.3620.2950.4750.144

Table 5a to Appendix 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.

Color Luminance Factor (Y%) Minimum Maximum White35 Yellow25 Red615 Blue514 Purple515

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.

Color Chromaticity Coordinates 1 2 3 4 x y x y x y x y White0.4800.4100.4300.3800.4050.4050.4550.435 Yellow0.5750.4250.5080.4150.4730.4530.5100.490 Purple0.3380.0800.4250.3650.4700.3850.6350.221

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.

Table 7 to Appendix to Part 655, Subpart F—Daytime Color Specification Limits for Non-Retroreflective Materials Used for Colored Pavements

Color Chromaticity coordinates 1 2 3 4 x y x y x y x y Green0.2300.7140.2660.4600.3670.4800.3670.584 Red0.4200.3300.4500.3800.5600.3700.5400.320
[67 FR 49572, July 31, 2002, as amended at 67 FR 70163, Nov. 21, 2002; 68 FR 65582, 65583, Nov. 20, 2003; 74 FR 66862, 66863, Dec. 16, 2009; 88 FR 87695, Dec. 19, 2023]