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For field work, our engineers and instruments mobilise anywhere in India — highway corridors, bridges, plants and greenfield alignments included.
Sign board retroreflectivity testing to IRC 67 and IS 14588 — RA by sheeting type and colour checked against minimum values for highway signage
Traffic-sign retroreflectivity is measured with a retroreflectometer as the coefficient of retroreflection (RA) in cd/lux/m², checked against the sheeting class and the requirements of IRC 67. NKMPV measures sign board retroreflectivity across India.
The retroreflectometer test for sign boards measures the coefficient of retroreflection (RA) of retroreflective sheeting materials applied on highway sign boards. RA quantifies how effectively a sign returns light from vehicle headlamps back toward the driver, ensuring legibility and visibility at night.
The following parameters are measured during sign board retroreflectometer testing. Minimum RA values are specified per IS 14588 for different sheeting types and colours at the standard geometry of 0.2 degrees observation angle and -4 degrees entrance angle.
| Parameter | Value / Range | Unit | Standard |
|---|---|---|---|
| RA — White, Type I (Engineer Grade) | ≥ 50 | cd/lux/m2 | IS 14588 Table 1 |
| RA — White, Type III (High Intensity) | ≥ 250 | cd/lux/m2 | IS 14588 Table 1 |
| RA — White, Type IX (Diamond Grade) | ≥ 580 | cd/lux/m2 | IS 14588 Table 1 |
| RA — Yellow, Type III | ≥ 170 | cd/lux/m2 | IS 14588 Table 1 |
| RA — Green, Type III | ≥ 45 | cd/lux/m2 | IS 14588 Table 1 |
| RA — Red, Type III | ≥ 45 | cd/lux/m2 | IS 14588 Table 1 |
| Observation Angle | 0.2 degrees (standard) / 0.33 degrees | degrees | ASTM E810 |
| Entrance Angle | -4 degrees (standard) / +30 degrees | degrees | ASTM E810 |
Retroreflective Sheeting for Road Traffic Signs — Specification
Standard Test Method for Coefficient of Retroreflection of Retroreflective Sheeting Utilizing the Coplanar Geometry
Code of Practice for Road Signs
Standard Specification for Retroreflective Sheeting for Traffic Control
Specifications for Road and Bridge Works — Section 800 (Traffic Signs and Road Markings)
Handheld retroreflectometer for sign sheeting
Measures RA from 0 to 2,000 cd/lux/m2 at 0.2 degree observation angle and -4 degree entrance angle per ASTM E810
CalibratedNIST-traceable retroreflective reference plaques
Set of 3 plaques covering low, medium, and high RA ranges for daily instrument verification
CalibratedDigital lux meter with cosine-corrected sensor
Measures ambient illuminance from 0 to 200,000 lux for daytime visibility assessment of sign boards
CalibratedAluminium telescopic ladder (6 m reach)
Provides safe access to overhead and gantry-mounted sign boards for in-situ retroreflectivity measurement
CalibratedThe test team inventories all sign boards on the project stretch, recording each sign's location (chainage and side), type (regulatory, warning, informatory, guide), dimensions, sheeting type, and mounting height. A testing plan is prepared specifying the number of RA readings per sign — typically 5 readings at different positions across the sign face as per ASTM E810.
The portable retroreflectometer is calibrated using NIST-traceable reference plaques before each testing session. The calibration is verified by taking readings on the low, medium, and high reference standards and confirming they fall within the specified tolerance. Calibration records are maintained for inclusion in the test report.
The retroreflectometer is placed directly on the sign face at the designated measurement points. For each sign, a minimum of 5 RA readings are taken at different locations — covering the centre, four quadrants, and any areas of visible damage or discolouration. Readings are taken for each distinct colour area on the sign (white background, coloured legend, border). The instrument automatically records RA at the standard 0.2-degree observation angle and -4-degree entrance angle.
Alongside retroreflectivity measurements, each sign board is visually assessed for physical defects — including delamination, cracking, fading, chalking, edge lifting of sheeting, corrosion of the substrate, vandalism, and obstruction by vegetation. The sign orientation, tilt angle, and mounting height are verified against IRC 67 specifications. Photographic records are taken for each sign.
Average RA values for each sign are computed from the individual readings. Results are compared against minimum RA requirements specified in IS 14588 for the applicable sheeting type and colour. Signs that fall below the minimum threshold are flagged for replacement or re-sheeting. Percentage degradation from initial RA values is calculated where baseline data is available.
The test report includes a sign-by-sign inventory with chainage, GPS coordinates, photograph, sheeting type, measured RA values for each colour, compliance status against IS 14588, and recommendations for signs requiring replacement. Summary statistics — percentage of signs compliant, average RA by sheeting type, and degradation trends — are presented in tabular and graphical format.
NKMPV provides professional retroreflectometer testing services for traffic signs, road markings, and pavement delineation across India. We deliver accurate retroreflectivity measurements that ensure your traffic control devices meet IRC, MoRTH, and NHAI safety standards.
Our retroreflectometer testing helps highway authorities, contractors, and sign manufacturers verify that road signs and markings remain visible during nighttime and adverse weather conditions—critical for road user safety.
Retroreflectometer testing measures the coefficient of retroreflection (RA value) of traffic signs and road markings. This scientific measurement quantifies how effectively a sign or marking reflects vehicle headlight illumination back to the driver's eyes at night.
Unlike subjective visual inspection, retroreflectometer testing provides objective, repeatable measurements that determine whether signs meet minimum visibility standards. The test simulates nighttime driving conditions by measuring retroreflected light at specific observation and entrance angles defined by international standards.
Road signs and markings naturally deteriorate over time due to weathering, UV exposure, and traffic abrasion. Regular retroreflectometer testing identifies signs that no longer meet minimum retroreflectivity requirements and need replacement before they compromise road safety.
Traffic Sign Retroreflectivity Testing</strong> Comprehensive testing of all traffic sign types including regulatory signs, warning signs, informatory signs, and work zone signs. We measure retroreflection values at multiple points on each sign to assess overall performance.
Our retroreflectometer testing services comply with all applicable Indian and international standards:
IRC Standards:
MoRTH Specifications:
NHAI Requirements:
NKMPV utilizes advanced retroreflectometer equipment calibrated to international standards:
Different sign categories require different minimum retroreflectivity values:
Standards vary by sheeting type and project specifications. Contact us for specific requirements.
NHAI recommends annual retroreflectometer testing for high-speed corridors and critical intersections. Lower-volume roads may be tested every 2-3 years. New signs should be tested at installation.
RA measures sign retroreflection (coefficient of retroreflected luminance). RL measures road marking night visibility (retroreflection). Qd measures day visibility (luminance coefficient under diffuse illumination).
Yes. Portable retroreflectometers enable testing with minimal traffic disruption. We coordinate with authorities for safe testing operations on active roadways.
Test results represent conditions at the time of measurement. For compliance purposes, annual testing is recommended as retroreflectivity degrades continuously with environmental exposure.
We test all sheeting grades from Type I (engineering grade) through Type XI (high-intensity prismatic and microprismatic). Testing protocols are adjusted based on sheeting specifications.
Yes. Test reports include specific recommendations for sign replacement or maintenance based on measured values compared to minimum standards for your project.
Ensure your traffic signs and road markings meet safety standards and regulatory requirements. NKMPV's retroreflectometer testing provides the accurate, defensible data you need for effective highway safety management.
Contact us today for retroreflectometer testing services:
Request a detailed proposal and competitive quote for your highway safety testing project.
Each sign's RA readings are compared with the IRC 67 minimum for its sheeting class and colour, and signs below the threshold are flagged for replacement.
Our retroreflectometer is calibrated using NIST-traceable reference plaques and verified before every testing session. This ensures measurement accuracy and reproducibility across different field conditions.
Beyond RA measurement, we provide a comprehensive sign board condition audit covering physical defects, colour assessment, mounting compliance, orientation, and visibility obstruction — delivering an actionable report for maintenance planning.
We offer integrated retroreflectivity testing for both sign boards and road markings in a single site mobilisation, giving highway projects a complete signage and marking compliance assessment per MoRTH specifications.
Our field teams deploy across national and state highways in Haryana, Punjab, Himachal Pradesh, Uttarakhand, Rajasthan, and Chandigarh, servicing projects ranging from single-stretch audits to corridor-level sign inventories.
Retroreflectivity of road signs is the property that makes traffic signs visible at night when illuminated by vehicle headlamps. Measured in candela per lux per square metre (cd/lx/m²) using a portable sign retroreflectometer per IRC 67:2022 and ASTM E1709. The instrument applies a standard illumination geometry (typically 0.2° observation angle, −4° entrance angle) and measures the reflected light intensity. Used to verify microprismatic and engineering-grade sheeting retroreflective performance against IRC/ASTM standards. NKMPV tests both newly-installed signs (acceptance) and in-service signs (degradation surveys).
Per IRC 67:2022 Table 4, minimum coefficient of retroreflection (RA) at 0.2° observation / -4° entrance angle: Type IV (high-intensity microprismatic) white: 250 cd/lx/m²; Type III (high-intensity prismatic) white: 250; Type II (engineering grade) white: 70; Type I (low-end engineering grade) white: 50. Coloured sheeting has lower values: red 45 (Type III), yellow 170 (Type III), green 45 (Type III). National Highway signs typically specify Type IV microprismatic for primary signs and Type III for secondary. Re-test threshold for in-service signs: below 70% of new-sign minimum requires replacement.
Sign retroreflectivity testing procedure: (1) Sign sampling — random selection of 5-10% of signs per corridor (or all critical regulatory signs). (2) Surface cleaning — wipe with damp cloth to remove dust/road grime. (3) Instrument placement — portable retroreflectometer pressed against the sign face at the prescribed geometry. (4) Three readings per sign — at top, middle, and bottom of the sign face, averaged. (5) Comparison with IRC 67 minimum — flag below-threshold signs for replacement. (6) Daytime visual assessment — visible damage, peeling, fading, graffiti. (7) GPS-stamped photographic record of each tested sign. Standard NHAI corridor sign survey: 50-80 signs/day per crew, report in 7-10 working days.
Coverage
Wherever your project is, there are two ways to work with NKMPV on Sign Board Retroreflectivity Testing.
For field work, our engineers and instruments mobilise anywhere in India — highway corridors, bridges, plants and greenfield alignments included.
Distance is not a constraint for laboratory testing. Send samples to our Pinjore laboratory and receive the digital report on completion — the route most of our out-of-region clients use.
These are locations where we have completed projects — not the boundary of our service area. We mobilise across India on request. See full coverage & project locations →
Sign Board Retroreflectivity Testing is carried out to IS 14588:2017, ASTM E810, IRC 67:2012 and ASTM D4956, as listed in the Applicable Standards section of this page. Tell us the specification your project must comply with and the quotation will state the standard the work follows.
Our laboratory is at Pinjore, Haryana, within same-day reach of Chandigarh, Panchkula, Mohali, Ambala and the wider Tri-City. If you are further away, distance is not a constraint: our field team travels to site anywhere in India for on-site work, and for laboratory tests you can courier samples to the Pinjore lab and receive the report digitally. Clients across Punjab, Haryana, Himachal Pradesh, Delhi-NCR, Uttarakhand, Rajasthan, Uttar Pradesh, Jammu and Kashmir and Ladakh already work with us this way.
Yes. NKMPV operates pan-India. We have delivered projects across Chandigarh, Panchkula, Mohali, Ambala, Karnal, Kurukshetra, Yamunanagar, Hisar and beyond, and we mobilise to greenfield and remote corridors on request. The 18 locations listed on our site are the places we have already worked — not the limit of where we go.
Send us the project details — location, quantity, and the standard you need to comply with — and you get a written quotation, usually within one working day. Pricing depends on sample count, site access and mobilisation distance, so we quote per project rather than publishing a fixed rate. Call +91-82953-60108 or use the quote form; every quotation states the applicable IS/IRC standard.
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