Introduction
When selecting reflective sheeting for traffic signs and road safety applications, choosing the right grade is critical for visibility, durability, and regulatory compliance. Among 3M's most widely used prismatic reflective materials, 3M™ Diamond Grade™ 3940 and 3M™ High Intensity Prismatic 3930 are often compared.
Although both products use micro-prismatic technology and are designed for permanent traffic signage, they differ in performance level, optical design, and recommended applications. This article explains the key differences between 3M 3940 and 3M 3930 to help engineers, contractors, and buyers make the right choice.
Overview of 3M 3940 Reflective Sheeting
3M™ Diamond Grade™ Reflective Sheeting Series 3940 is a premium micro-prismatic reflective film designed for permanent traffic control signs requiring high brightness and long-distance visibility.
Key characteristics:
. Diamond Grade™ micro-prismatic technology
. ASTM D4956 Type IV
. High retroreflectivity with wide observation and entrance angles
. Expected outdoor service life up to 12 years (vertical exposure)
3940 is commonly used on high-speed roadways, highways, and critical guide signs where nighttime visibility is essential.
Overview of 3M 3930 Reflective Sheeting
3M™ High Intensity Prismatic Reflective Sheeting Series 3930 is a widely adopted Type IV reflective film that balances performance and cost for permanent traffic signs.
Key characteristics:
. High-intensity micro-prismatic structure
. ASTM D4956 Type IV
. Reliable brightness for standard road conditions
. Typical outdoor durability up to 10 years
3930 is often selected for general traffic signs, urban roadways, and projects where proven performance and cost efficiency are priorities.
Key Differences Between 3M 3940 and 3M 3930
1. Retroreflective Performance
Both materials meet ASTM Type IV requirements, but 3940 offers higher typical retroreflectivity, especially in white and fluorescent colors. This results in:
. Better long-distance recognition
. Improved visibility at wider viewing angles
. Enhanced performance on high-speed roads
3930 provides stable and compliant reflectivity but is optimized for standard visibility requirements.
2. Optical Design
. 3940 uses Diamond Grade™ micro-prismatic optics, designed to maximize light return across a wider range of entrance angles.
. 3930 uses a high-intensity prismatic design optimized for conventional traffic sign geometry.
This difference makes 3940 more suitable for complex road layouts, curves, and multi-lane highways.
3. Durability & Service Life
| Item | 3M 3940 | 3M 3930 |
|---|---|---|
| Expected Outdoor Life | Up to 12 years | Up to 10 years |
| UV & Weather Resistance | Excellent | Very good |
| Recommended Installation | Vertical | Vertical |
3940 is often chosen for long-term infrastructure projects where replacement cycles need to be minimized.
4. Cost & Project Positioning
3940: Higher initial cost, higher performance, longer service life
3930: More economical, widely used, suitable for large-volume standard projects
The choice usually depends on project budget, road speed, and visibility requirements.
Typical Applications Comparison
3M 3940 Applications
. Highway guide signs
. Expressways and high-speed roads
. Critical warning and regulatory signs
. Areas requiring maximum nighttime visibility
3M 3930 Applications
. Urban and rural traffic signs
. Regulatory and warning signs
. General permanent road signage
. Cost-sensitive infrastructure projects
How to Choose Between 3M 3940 and 3M 3930
Choose 3M 3940 if your project requires:
. Maximum brightness and long-distance visibility
. Wide-angle performance
. Longer service life and reduced maintenance
Choose 3M 3930 if your project prioritizes:
. Proven ASTM Type IV compliance
. Balanced performance and cost
. Large-scale standard traffic signage
Conclusion
Both 3M 3940 and 3M 3930 are high-quality micro-prismatic reflective sheetings designed for permanent traffic control applications. While they share the same ASTM Type IV classification, 3940 delivers higher optical performance and longer durability, whereas 3930 remains a reliable and cost-effective industry standard.
Understanding these differences helps ensure the right reflective material is selected for safety, compliance, and long-term value.
