IRC 67 Traffic Sign Boards Specifications & Guidelines
The authoritative Indian Roads Congress benchmark for highway signage fabrication, retro-reflective classes, and road safety compliance.
What is IRC 67?
IRC 67 is the official Code of Practice for Road Signs published by the Indian Roads Congress (IRC). It is the premier engineering standard referenced by the Ministry of Road Transport and Highways (MoRTH), National Highways Authority of India (NHAI), State Public Works Departments (PWD), and municipal traffic planning authorities.
The standard lays down uniform principles for the design, sizing, shape, color, typography, illumination, retro-reflectivity, and roadside placement of road signs throughout India.
Purpose & Engineering Relevance of IRC 67
The fundamental premise of IRC 67 is that drivers travelling at high speeds cannot afford ambiguous visual cues. Standardizing every road sign across all states ensures that a driver immediately understands the sign without hesitation.
- Uniform Recognition: Identical symbols ensure language barriers across Indian states do not hinder safety.
- Legibility Distances: Letter heights and board dimensions are mathematically matched to road operating speeds.
- Nighttime Safety: Mandates minimum retro-reflective luminance so signs are visible under headlamp illumination without requiring external electric street lights.
Traffic Sign Categories Under IRC 67
IRC 67 organizes all road signs into three distinct categories:
Equilateral triangles with red retro-reflective borders and white or yellow backgrounds. Sized at 600mm, 750mm, or 900mm depending on road speed class.
Circular signs with red borders and white or blue backgrounds, along with the octagonal STOP sign and inverted triangular GIVE WAY sign.
Rectangular destination boards, route markers, and facility signs color-coded by highway hierarchy (green for NH/SH, blue for Expressways and urban roads).
Retro-Reflective Sheeting Classes in IRC 67
IRC 67 mandates microprismatic retro-reflective sheeting categorized into standard performance classes:
| Sheeting Class | Technology | Mandated IRC 67 Application |
|---|---|---|
| Type XI (Diamond / Full Cube) | Full-Cube Microprismatic | Overhead Gantry Signs, Expressways & Critical Curves |
| Type IV (High Intensity Prismatic) | Microprismatic | National & State Highways, Roadside Informatory & Cautionary Signs |
| Type I (Engineering Grade) | Enclosed Lens / Basic | Rural Roads, Low-speed private campuses, temporary parking |
Manufacturing & Fabrication Specifications
Traffic sign boards built to IRC 67 must feature corrosion-resistant substrates:
- Substrate: Aluminum Composite Material (ACM 3mm / 4mm) or Galvanized Iron (GI 1.5mm / 2.0mm).
- Sheeting: High-intensity retro-reflective microprismatic sheeting.
- Font & Lettering: Transport Medium font with approved stroke width and kerning schedules.
- Technical Verification: [VERIFIED IRC 67 SPECIFICATION TO BE ADDED]
Frequently Asked Questions
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