PART 655—TRAFFIC OPERATIONS Authority: 23 U.S.C. 101(a), 104, 109(d), 114(a), 217, 315, and 402(a); 23 CFR 1.32; and 49 CFR 1.85. Subparts A-E [Reserved] Subpart F—Traffic Control Devices on Federal-Aid and Other Streets and Highways Source: 48 FR 46776, Oct. 14, 1983, unless otherwise noted. § 655.601 Purpose. To prescribe the policies and procedures of the Federal Highway Administration (FHWA) to obtain basic uniformity of traffic control devices on all streets and highways in accordance with the following references that are approved by the FHWA for application on Federal-aid projects: (a) MUTCD. (b) AASHTO Guide to Metric Conversion. (c) AASHTO Traffic Engineering Metric Conversion Factors. (d) The material listed in this paragraph (a) of this section is incorporated by reference into this section with the approval of the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. To enforce any edition other than that specified in this section, the FHWA must publish a document in the Federal Register https://ops.fhwa.dot.gov/contactus.htm. [email protected], www.archives.gov/federal-register/cfr/ibr-locations.html. (1) AASHTO, American Association of State Highway and Transportation Officials, Suite 249, 444 North Capitol Street NW., Washington, DC 20001 (i) AASHTO Guide to Metric Conversion, 1993; (ii) AASHTO, Traffic Engineering Metric Conversion Factors, 1993—Addendum to the Guide to Metric Conversion, October 1993. (2) FHWA, Federal Highway Administration, 1200 New Jersey Avenue SE., Washington, DC 20590, telephone (202) 366-1993, also available at http://mutcd.fhwa.dot.gov. (i) Manual on Uniform Traffic Control Devices for Streets and Highways (MUTCD), 11th Edition, December 2023, with Revision 1 incorporated, FHWA, December 2025. (ii) [Reserved] [77 FR 28466, May 14, 2012, as amended at 87 FR 47931, Aug. 5, 2022; 88 FR 87695, Dec. 19, 2023; 91 FR 10773, Mar. 5, 2026] § 655.602 Definitions. The terms used herein are defined in accordance with definitions and usages contained in the MUTCD and 23 U.S.C. 101(a). § 655.603 Standards. (a) National MUTCD. (b) State or other Federal MUTCD. (2) States and other Federal agencies are encouraged to adopt the National MUTCD in its entirety as their official Manual on Uniform Traffic Control Devices. (3) States and other Federal agencies shall adopt changes issued by the FHWA to the National MUTCD within two years from the effective date of the final rule. For those States that automatically adopt the MUTCD immediately upon the effective date of the latest edition or revision of the MUTCD, the FHWA Division Administrators have the flexibility to allow these States to install certain devices from existing inventory or previously approved construction plans that comply with the previous MUTCD during the two-year adoption period. (c) Color specifications. 1 1 (d) Compliance Existing highways (2) New or reconstructed highways. (3) Construction area activities. [48 FR 46776, Oct. 14, 1983, as amended at 51 FR 16834, May 7, 1986; 68 FR 14139, Mar. 24, 2003; 71 FR 75115, Dec. 14, 2006; 74 FR 28442, June 16, 2009; 74 FR 66861, Dec. 16, 2009; 88 FR 87695, Dec. 19, 2023] § 655.604 Achieving basic uniformity. (a) Programs. (b) Inventory. [48 FR 46776, Oct. 14, 1983, as amended at 71 FR 75115, Dec. 14, 2006] § 655.605 Project procedures. (a) Federal-aid highways. (b) Off-system highways. § 655.606 Higher cost materials. The use of signing, pavement marking, and signal materials (or equipment) having distinctive performance characteristics, but costing more than other materials (or equipment) commonly used may be approved by the FHWA Division Administrator when the specific use proposed is considered to be in the public interest. § 655.607 Funding. (a) Federal-aid highways. (2) Traffic control devices are eligible, in keeping with paragraph (a)(1) of this section, provided that the work is classified as construction in accordance with 23 U.S.C. 101(a) and the State or local agency has a policy acceptable to the FHWA Division Administrator for selecting traffic control devices material or equipment based on items such as cost, traffic volumes, safety, and expected service life. The State's policy should provide for cost-effective selection of materials which will provide for substantial service life taking into account expected and necessary routine maintenance. For these purposes, effectiveness would normally be measured in terms of durability, service life and/or performance of the material. Specific projects including material or equipment selection shall be developed in accordance with this policy. Proposed work may be approved on a project-by-project basis when the work is (i) clearly warranted, (ii) on a Federal-aid system, (iii) clearly identified by site, (iv) substantial in nature, and (v) of sufficient magnitude at any given location to warrant Federal-aid participation as a construction item. (3) The method of accomplishing the work will be in accordance with 23 CFR part 635, subpart A, Contract Procedures. (b) Off-system 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 D 65 3. For fluorescent retroreflective materials ASTM E991 may be used to determine the chromaticity provided that the D 65 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 D 65 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 0.302 0.064 0.310 0.210 0.380 0.255 0.468 0.140 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 D 65 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 0.033 0.370 0.180 0.370 0.230 0.240 0.091 0.133 Purple 0.355 0.088 0.385 0.288 0.500 0.350 0.635 0.221 Light Blue Chromaticity coordinates are yet to be determined. Note: 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 D 65 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 Fluorescent Pink 0.450 0.270 0.590 0.350 0.644 0.290 0.536 0.230 Fluorescent Red 0.666 0.334 0.613 0.333 0.671 0.275 9.735 0.265 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 D 65 Color Luminance Factor Limits (Y) Min Max Y F Fluorescent Orange 25 None 15 Fluorescent Yellow 45 None 20 Fluorescent Yellow-Green 60 None 20 Fluorescent Green 20 30 12 Fluorescent Pink 25 None 15 Fluorescent Red 20 30 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 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 Fluorescent Red 0.680 0.320 0.645 0.320 0.712 0.253 0.735 0.265 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 D 65 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 Purple 0.300 0.064 0.309 0.260 0.362 0.295 0.475 0.144 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 D 65 Color Luminance Factor (Y%) Minimum Maximum White 35 Yellow 25 Red 6 15 Blue 5 14 Purple 5 15 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 Purple 0.338 0.080 0.425 0.365 0.470 0.385 0.635 0.221 Note: 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 Green 0.230 0.714 0.266 0.460 0.367 0.480 0.367 0.584 Red 0.420 0.330 0.450 0.380 0.560 0.370 0.540 0.320 [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] Subpart G [Reserved]