02-19140. Traffic Control Devices on Federal-Aid and Other Streets and Highways; Color Specifications for Retroreflective Sign and Pavement Marking Materials

AGENCY:

Federal Highway Administration (FHWA), DOT.

ACTION:

Final rule.

SUMMARY:

The FHWA is revising its color specifications for retroreflective signing materials. The current color specifications used in traffic control were developed in the late 1960's. The technological advances in the manufacturing of signing and markings materials and the measurement of color have required the FHWA to revise and expand the color specifications. This revision includes daytime and nighttime specifications for both assigned and unassigned colors found in the Manual on Uniform Traffic Control Devices (MUTCD). The FHWA is adding daytime and nighttime specifications for retroreflective pavement marking materials. The materials are required to provide the specified colors under the identified measurement protocols throughout service life.

EFFECTIVE DATE:

This final rule is effective August 30, 2002.

FOR FURTHER INFORMATION CONTACT:

For technical information: Mr. Ernest Huckaby, Office of Transportation Operations (HOTO), [phone]. For legal information: Mr. Raymond Cuprill, Office of the Chief Counsel (HCC-40), [phone], Federal Highway Administration, 400 Seventh Street, SW., Washington, D.C. 20590-0001. Office hours are from 7:45 a.m. to 4:15 p.m., e.t., Monday through Friday, except Federal holidays.

SUPPLEMENTARY INFORMATION:

Electronic Access

This document, the NPRM, and all comments received may be viewed online through the Document Management System (DMS) at: http://dms.dot.gov. The DMS is available 24 hours each day, 365 days each year. Electronic submission and retrieval help and guidelines are available under the help section of the web site.

An electronic copy of this document may also be downloaded by using a computer, modem and suitable communications software from the Government Printing Office's Electronic Bulletin Board Service at [phone]. Internet users may also reach the Office of the Federal Register's home page at: http://www.nara.gov/​fedreg and the Government Printing Office's web page at: http://www.access.gpo.gov.

The current color specifications are on file at the Office of the Federal Register, 800 North Capitol Street, NW., 7th Floor, Suite 700, Washington, DC 20408, and are available for inspection and copying at the FHWA, Office of Transportation Operations, Room 3408, 400 7th St., SW., Washington, DC 20590, as prescribed in 49 CFR part 7.

Background

This final rule is based on the FHWA's notice of proposed rulemaking (NPRM), Traffic Control Devices on Federal-Aid and Other Streets and Highways; Color Specifications for Retroreflective Sign and Pavement Marking Materials, published in the Federal Register on December 21, 1999, at 64 FR 71354. All comments received in response to the NPRM have been considered in adopting this final rule. These comments are discussed in the section entitled “Discussion of Comments.”

The MUTCD is incorporated by reference in 23 CFR 655.601. The color specifications are found in the appendix to subpart F of part 655.

The current specifications for the color of retroreflective sign sheeting were determined on the basis of material available nearly 20 years ago. Since then, new microprismatic material has been commercially available and the original CIE ^[1] Illuminant C has been replaced with CIE Illuminant D₆₅. In addition, an extensive international effort is in progress to specify the nighttime appearance of retroreflective materials. Lastly, expanding the specifications to include fluorescent materials is also necessary at this time since these materials are used on several traffic signs. In addition to revising the daytime color specifications for retroreflective sign sheeting material used primarily for traffic signs, color specifications for pavement markings and markers are included in this revision.

Discussion of Comments

Interested persons were invited to participate in the development of this final rule by submitting written or electronic comments on the NPRM to FHWA Docket No. FHWA-99-6190 on or before June 21, 2000. The FHWA received 21 comments to the docket (6 from State and local DOTs; 7 from industry; 4 from associations; 3 from institutes/universities; and 1 Federal agency). The FHWA received significant comments that included concerns with the availability and cost of the laboratory equipment used, concerns with the use of illuminant D₆₅ for evaluating the performance of luminescent for fluorescent materials, the use of luminescent luminance factor (Y_F) for fluorescent materials.

The FHWA believes the amount of information presented in the tables published in the NPRM may be overwhelming in content and confusing. The FHWA has placed the “luminance” values in a separate table (i.e., 1a, 3a, and 5a). It is important for users to know that these sub-tables should be read together in order to define the correct color requirement.

Commenters recommended that FHWA provide the appropriate references for types of sheeting material for retroreflective materials. A breakdown of sheeting type has been added as Table 1a.

Another concern identified through several comments was the lack of human factors research related to driver recognition of sign colors. The discussion of human factors research is beyond the scope of this rulemaking and will be addressed in the future. While laboratory studies have indicated that human observers require fairly small color regions to achieve a high degree of agreement (greater than 90 percent) for color naming, there have been no studies with forced choices. That is, when presented with a variety of samples spanning colors within a given color region, responses will vary. Additional studies are needed wherein the observer is forced to choose between specified color names to determine if samples taken from near the allowable color region boundaries might be mistaken for a neighboring color. Pending such studies, however, there are no indications that the existing color system should be modified. The color regions in the final rule are not significantly different from previously defined color regions and should not be changed without substantial indication of inadequacy.

Several commenters recommended that color specifications for the color “fluorescent red” be included in the specifications. Fluorescent red was not proposed in Tables 3 or 4 of the NPRM and it is beyond the scope of this rulemaking. However, this color will be addressed in future rulemaking, which will allow the public the opportunity to comment on the proposed specification.

The FHWA adopts, with some changes, the proposed Table 1 to Part 655, Subpart F, Daytime Color Specification Limits for Retroreflective Material with CIE 2 Degree Standard Observer and 45/0 (0/45) Geometry and CIE Standard Illuminant D₆₅. The American Society for Testing and Materials (ASTM) sets industry standards for defining daytime sign color. It also established a standard addressing color specifications. With few exceptions, Table 1 is the same as this standard.

The color specifications for “white” have been adjusted from table 1, proposed in the NPRM, which results in a slight enlargement of the color region in all directions. This slightly larger color region will not result in loss of color differentiation between white and other colors as long as differences in the daytime luminance factors are maintained.

The color specifications for “orange” have been adjusted from the proposed table by adjusting the red border which allows a slightly shorter wavelength hue line than that proposed in the NPRM. This results in a slightly greater separation between the red and orange color regions which will aid in daytime color recognition.

The “purple” color specifications have been modified to reflect the colors actually in use. Several commenters pointed out that specifying precise color regions for unassigned colors may be premature. Accordingly, a revised color region, incorporating both the hues from the initial proposal in the NPRM and the existing commercial materials, are recommended. As use of the materials is further refined, the purple color box may be optimized or even separated into two distinct colors.

The “coral” and “yellow-green” color specifications have been removed from this table. Several commenters mentioned that there are no studies that indicate yellow-green or coral are effective signing colors. The FHWA has adopted the color “fluorescent yellow-green” for use with pedestrian, school, and bicycle crossing warning signs and has included color specifications in Table 3.

The color “fluorescent coral” is being proposed for use in incident management and is being considered under FHWA Docket No. FHWA-2001-11159, published at 67 FR 35850 on May 21, 2002.

In response to several docket comments, we have removed the color “black” from the table. Black sheeting used in traffic control signage is not a retroreflective product. Commercially available vinyl elastomeric films meet all the requirements for a high-contrast legend material.

We have added Table 1a to part 655, Subpart F, Daytime Luminance Factors (percent) for Retroreflective Material with CIE 2 Degree Standard Observer and 45/0 (0/45) Geometry and CIE Standard Illuminant D₆₅, in order to be consistent with the format found in ASTM Standard Specification D4956-01^[2] which provides three separate tables of daytime luminance factors (Y) for retroreflective materials: One for ASTM Types I, II, III and VI sheeting; one for ASTM Types IV, VII, VIII, and IX; and the third for ASTM Type V sheeting. The different manufacturing techniques for the various ASTM types have resulted in varying luminance factors. ASTM Type V is metallized microprismatic retroreflecting material used primarily for delineators. This material is not the predominant daytime signal, but provides a nighttime signal for delineation.

The FHWA has adopted Table 2 to part 655, Subpart F, Nighttime Color Specification Limits for Retroreflective Material With CIE 2 Degree Standard Observer and Observation Angle of 0.33 Degrees, Entrance Angle of Plus 5 Degrees and CIE Standard Illuminant A, with very minor changes. The color specifications for the color “orange” have been reordered and the two missing coordinates for the color “red” have been added. The color “coral” has been removed from the table for reasons given in the preamble discussion for Table 1. At present there are no known instruments available for field measurement of nighttime color.

The FHWA has adopted Table 3 to Part 655, Subpart F, Daytime Color Specification Limits for Fluorescent Retroreflective Material With CIE 2 Degree Standard Observer and 45/0 (0/45) Geometry and CIE Standard Illuminant D₆₅. The contents of Tables 3 and 4 reflect the general comments received in response to the docket. The white boundaries for fluorescent colors have been shifted closer to the chromaticity diagram loci from those positions proposed in the NPRM in response to comments that color saturation is as important as luminance to achieve high conspicuity for colored materials.

The FHWA has added Table 3a to Part 655, Subpart F, Daytime Luminance Factors (Percent) for Fluorescent Retroreflective Material With CIE 2 Degree Standard Observer and 45/0 (0/45) Geometry and CIE Standard Illuminant D₆₅, which contains the luminance factors found in Table 3 proposed in the NPRM for easier recognition. Specifying the requirements for high-conspicuity (fluorescent) materials by using daytime luminance factors under CIE Standard Illuminants D₆₅ and D₁₅₀ (analogous to noontime and twilight) have been extensively discussed with the ASTM. There is disagreement over the use of the fluorescent luminance factor (Y_F) as a material requirement since Y_F cannot be measured in the field at this time. As an interim step, the FHWA is defining high-conspicuity materials using a value for the daytime luminance factor that roughly equals 70 percent of the MacAdam Limit ^[3] for a color near the centroid of the color region. The fluorescent luminance factor (Y_F) for high-conspicuity materials is provided as a provision for quality control by manufacturers, and is not recommended as a measurement of materials performance for acceptance or while in service.

Table 4 to part 655, Subpart F, Nighttime Color Specification Limits for Fluorescent Retroreflective Material With CIE 2 Degree Standard Observer and Observation Angle of 0.33 Degree, Entrance Angle of Plus 5 Degrees and CIE Standard Illuminant A, is adopted with only a slight re-ordering of the x,y coordinates for consistency. At present there are no known instruments available for field measurement of nighttime color.

Table 5 to part 655, Subpart F, Daytime Color Specification Limits for Retroreflective Pavement Marking Material With CIE 2 Degree Standard Observer and 45/0 (0/45) Geometry and CIE Standard Illuminant D₆₅, is adopted with only a slight re-ordering of the x,y coordinates for consistency.

Table 5a part 655, Subpart F, Daytime Luminance Factors (Percent) for Retroreflective Pavement Marking Material With CIE 2Degree Standard Observer and 45/0 (0/45) Geometry and CIE Standard Illuminant D₆₅, is added and, for easier recognition, contains the luminance factors found in the Table 5 proposed in the NPRM. The luminance factor (Y) for white and yellow pavement marking materials proposed in the NPRM were significantly higher than values typically measured on the National Transportation Product Evaluation Program test decks after a fairly short period of time. The FHWA deleted the column heading “Without Glass Beads” as the materials should be measured in the manner they are intended to be used, which includes the glass beads.

Table 6 to part 655, subpart F, Nighttime Color Specification Limits for Retroreflective Pavement Marking Material with CIE 2 Degree Standard Observer, Observation Angle of 1.05 Degrees, Entrance Angle of Plus 88.76 Degrees and CIE Standard Illuminant A, is adopted in the final rule with a modification to what was proposed in the NPRM to the yellow pavement marking materials. The proposed specifications did not provide sufficient separation between yellow and white, leading to the potential loss of color recognition at night. This specification corrects that problem.

Executive Order 12866 (Regulatory Planning and Review) and U.S. DOT Regulatory Policies and Procedures

The FHWA has determined that this action is not a significant regulatory action within the meaning of Executive Order 12866 or significant within the meaning of the U.S. Department of Transportation regulatory policies and procedures. The economic impact of this rulemaking will be minimal. Although the new specifications have been revised to incorporate the latest research, the basic criteria remain essentially the same. These changes will not adversely affect, in a material way, any sector of the economy. In addition, these changes will not interfere with any action taken or planned by another agency and will not materially alter the budgetary impact of any entitlements, grants, user fees, or loan programs. Consequently, a full regulatory evaluation is not required.

Regulatory Flexibility Act

In compliance with the Regulatory Flexibility Act (5 U.S.C. 601-612), the FHWA has evaluated the effects of this action on small entities and has determined that this action will not have a significant economic impact on a substantial number of small entities. As stated above, although the FHWA has amended this final rule to incorporate the latest research, the basic criteria remain essentially the same. For these reasons, the FHWA certifies that this action will not have a significant economic impact on a substantial number of small entities.

Unfunded Mandates Reform Act of 1995

This rule will not impose unfunded mandates as defined by the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4, March 22, 1995, 109 Stat. 48). This rule will not result in the expenditure by State, local, and tribal governments, in the aggregate, or by the private sector, of $100 million or more in any one year (2 U.S.C. 1531 et seq).

Executive Order 12630 (Taking of Private Property)

This rule will not effect a taking of private property or otherwise have taking implications under Executive Order 12630, Governmental Actions and Interface with Constitutionally Protected Property Rights.

Executive Order 12988 (Civil Justice Reform)

This action meets applicable standards in sections 3(a) and 3(b)(2) of Executive Order 12988, Civil Justice Reform, to minimize litigation, eliminate ambiguity, and reduce burden.

Executive Order 13045 (Protection of Children)

We have analyzed this action under Executive Order 13045, Protection of Children from Environmental Health Risks and Safety Risks. This rule is not an economically significant rule and does not concern an environmental risk to health or safety that may disproportionately affect children.

Executive Order 13132 (Federalism)

This action has been analyzed in accordance with the principles and criteria contained in Executive Order 13132, dated August 4, 1999, and the FHWA has determined that this action does not have sufficient federalism implications to warrant the preparation of a Federalism assessment. The FHWA has also determined that this action will not preempt any State law or State regulation or affect the States' ability to discharge traditional State governmental functions.

Executive Order 12372 (Intergovernmental Review)

Catalog of Federal Domestic Assistance Program Number 20.205, Highway Planning and Construction. The regulations implementing Executive Order 12372 regarding intergovernmental consultation on Federal programs and activities apply to this program.

Paperwork Reduction Act

Under the Paperwork Reduction Act of 1995 (PRA) (44 U.S.C. 3501, et seq.), Federal agencies must obtain approval from the Office of Management and Budget (OMB) for each collection of information they conduct, sponsor, or require through regulations. The FHWA has determined that this action does not contain collection of information requirements for the purposes of the PRA.

National Environmental Policy Act

The FHWA has analyzed this action for the purpose of the National Environmental Policy Act of 1969 (42 U.S.C. 4321 et seq.) and has determined that this action will not have any effect on the quality of the environment.

Executive Order 13175 (Tribal Consultation)

The FHWA has analyzed this action under Executive Order 13175, dated November 6, 2000, and believes that it will not have substantial direct effects on one or more Indian tribes; will not impose substantial direct compliance costs on Indian tribal governments; and will not preempt tribal law. Therefore, a tribal summary impact statement is not required.

Executive Order 13211 (Energy Effects)

We have analyzed this rule under Executive Order 13211, Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use. We have determined that it is not a significant energy action under that order because it is not a significant regulatory action under Executive Order 12866 and is not likely to have a significant adverse effect on the supply, distribution, or use of energy. Therefore, a Statement of Energy Effects under Executive Order 13211 is not required.

Regulation Identification Number

A regulation identification number (RIN) is assigned to each regulatory action listed in the Unified Agenda of Federal Regulations. The Regulatory Information Service Center publishes the Unified Agenda in April and October of each year. The RIN contained in the heading of this document can be used to cross reference this action with the Unified Agenda.

List of Subjects in 23 CFR Part 655

• Design standards
• Grant programs—transportation
• Highways and roads
• Incorporation by reference
• Signs
• Traffic regulations

Issued on: July 23, 2002.

Mary E. Peters,

Federal Highway Administrator.

In consideration of the foregoing, the FHWA is amending title 23, Code of Federal Regulations, part 655, as set forth below:

PART 655—[AMENDED]

1. The authority citation for part 655 continues to read as follows:

Authority: 23 U.S.C. 101(a), 104, 109(d), 114(a), 217, 315, and 402(a); 23 CFR 1.32; and 49 CFR 1.48(b).

2. Revise the appendix to subpart F to read as follows:

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. Traffic control materials shall maintain the colors and luminance factors provided in the appropriate tables throughout service. 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
White	0.303	0.300	0.368	0.366	0.340	0.393	0.274	0.329
Red	0.648	0.351	0.735	0.265	0.629	0.281	0.565	0.346
Orange	0.558	0.352	0.636	0.364	0.570	0.429	0.506	0.404
Brown	0.430	0.340	0.430	0.390	0.518	0.434	0.570	0.382
Yellow	0.498	0.412	0.557	0.442	0.479	0.520	0.438	0.472
Green	0.026	0.399	0.166	0.364	0.286	0.446	0.207	0.771
Blue	0.078	0.171	0.150	0.220	0.210	0.160	0.137	0.038
Light Blue	0.180	0.260	0.240	0.300	0.270	0.260	0.230	0.200
Purple	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.

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
White	27		40		15
Red	2.5	12	3.0	15	2.5	11
Orange	14	30	12	30	7.0	25
Brown	4.0	9.0	1.0	6.0	1.0	9.0
Yellow	15	45	24	45	12	30
Green	3.0	9.0	3.0	12	2.5	11
Blue	1.0	10	1.0	10	1.0	10
Light Blue	12	40	18	40	8.0	25
Purple	2.0	10	2.0	10	2.0	10

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
	x	y	x	y	x	y	x	y
White	0.475	0.452	0.360	0.415	0.392	0.370	0.515	0.409
Red	0.650	0.348	0.620	0.348	0.712	0.2550	0.735	0.265
Orange	0.595	0.405	0.565	0.405	0.613	0.355	0.643	0.355
Brown	0.595	0.405	0.540	0.405	0.570	0.365	0.643	0.355
Yellow	0.513	0.487	0.500	0.4700	0.545	0.425	0.572	0.425
Green	0.007	0.570	0.200	0.500	0.322	0.590	0.193	0.782
Blue	0.33	0.370	0.180	0.370	0.230	0.240	0.091	0.133
Light Blue	Chromaticity coordinates are yet to be determined.
Purple	Chromaticity 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 Orange	0.583	0.416	0.535	0.400	0.595	0.351	0.645	0.355
Fluorescent Yellow	0.479	0.520	0.446	0.483	0.512	0.421	0.557	0.442
Fluorescent Yellow-Green	0.387	0.610	0.369	.546	.428	.496	0.460	0.540
Fluorescent Green	0.210	0.770	0.232	0.656	0.320	0.590	0.320	0.675

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 Orange	25	None	15
Fluorescent Yellow	45	None	20
Fluorescent Yellow-Green	60	None	20
Fluorescent Green	20	30	12
*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 Orange	0.625	0.375	0.589	0.376	0.636	0.330	0.669	0.331
Fluorescent Yellow	0.554	0.445	0.526	0.437	0.569	0.394	0.610	0.390
Fluorescent Yellow-Green	0.480	0.520	0.473	0.490	0.523	0.440	0.550	0.449
Fluorescent 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.

Color	Chromaticity Coordinates
	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	0.375
Yellow	0.560	0.440	0.490	0.510	0.420	0.440	0.460	0.400
Red	0.480	0.300	0.690	0.315	0.620	0.380	0.480	0.360
Blue	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.

Color	Luminance Factor (Y%)
	Minimum	Maximum
White	35
Yellow	25
Red	6	15
Blue	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.

Color	Chromaticity Coordinates
	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	0.435
Yellow	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.

Footnotes

1.  International Commission on Illumination.

2.  ASTM Standard D4956-01a, Standard Specification for Retroreflective Sheeting for Traffic Control. Copies of this standard may be obtained by contacting ASTM at ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959 or through the ASTM website (www.astm.org).

3.  The MacAdam Limit is the theoretical maximum luminance factor achievable for a reflective color under a given illuminant. Values range from 100 percent, for ideal white, to 0 percent for ideal black.