ASTM D6628-23 PDF

Overview

ASTM D6628-23: Standard Specification for Color of Retroreflective Pavement Marking Materials defines standardized color requirements for retroreflective pavement marking materials used in traffic control lane markings and road surface symbols. Developed by ASTM International, this standard addresses both painted and tape lines, including materials such as thermoplastic, epoxy, and other types containing retroreflective optics. The specification focuses solely on the daytime and nighttime color characteristics-primarily chromaticity limits and daytime lightness-ensuring consistent visibility and compliance across road marking installations.

Scope Highlights

• Applies to all retroreflective pavement markings with surface optics, excluding structured pavement markings and those without retroreflective features.
• Specifies color performance requirements for both newly applied and in-service pavement markings.
• Relies on SI units, but allows degrees for retroreflection geometry in line with international practices.

Key Topics

Daytime and Nighttime Color Requirements

• Chromaticity Limits: Pavement markings must meet specific chromaticity coordinates for distinct colors (white, yellow, red, blue, purple) under both daylight and nighttime conditions.
• Lightness (Luminance) Factor: Daytime markings must conform to minimum and, for some colors, maximum luminance factor (Y tristimulus value) percentages, as measured by spectrophotometry.

Retroreflective Optics

• Covers materials embedded with glass beads or composite optics to ensure retroreflective performance under vehicle headlights.
• Excludes structured pavement markings that have raised surfaces designed for special effects or enhanced wet visibility.

Measurement & Testing

• Daytime color is measured using 45/0 (or 0/45) geometry with CIE illuminant D65 following ASTM E1349.
• Nighttime color is measured per ASTM E811 or by portable retroreflection colorimeter according to ASTM E2367.
• Testing is intended for installed materials in clean, dry conditions to ensure accurate color assessment.

Performance Throughout Service Life

• The specification provides guidance for evaluating both newly applied and in-service markings, with considerations for factors such as traffic volume, environmental exposure, and pavement type.
• Recognizes that color performance may degrade over time due to wear and environmental impacts.

Applications

• Roadway Safety: Ensures that lane lines, traffic symbols, and other pavement markings remain visible both day and night, aiding in driver guidance and reducing roadway accidents.
• Regulatory Compliance: Supports agencies and contractors in meeting federal and local requirements for pavement marking color, improving consistency in public infrastructure.
• Material Selection & Procurement: Serves as a quality benchmark for selecting and approving road marking materials.
• Maintenance & Inspection: Guides ongoing assessment of in-service markings for compliance, informing maintenance and replacement strategies to uphold visibility standards.

Related Standards

• ASTM D4061: Test Method for Retroreflectance of Horizontal Coatings
• ASTM D4505: Specification for Preformed Retroreflective Pavement Marking Tape for Extended Service Life
• ASTM D4592: Specification for Preformed Retroreflective Pavement Marking Tape for Limited Service Life
• ASTM D7585/D7585M: Practice for Evaluating Retroreflective Pavement Markings with Portable Instruments
• ASTM E284: Terminology of Appearance
• ASTM E308: Practice for Computing the Colors of Objects Using the CIE System
• ASTM E811: Practice for Measuring Colorimetric Characteristics of Retroreflectors under Nighttime Conditions
• ASTM E1349: Test Method for Reflectance Factor and Color by Spectrophotometry
• ASTM E2367: Test Method for Measurement of Nighttime Chromaticity with Portable Colorimeter
• 23 CFR Chapter 1, Part 655: Federal regulations for Traffic Control Devices

Keywords: retroreflective pavement markings, pavement marking color, ASTM D6628, traffic control markings, road marking visibility, chromaticity, luminance factor, reflective pavement materials, marking specification standards.