The Indian government has introduced new rules under the Legal Metrology (General) Amendment Rules, 2025, specifically addressing the use of radar equipment for measuring vehicle speed. These rules, set to come into force on July 1, 2025, aim to standardize the operation, construction, and testing of radar speed measurement devices used for traffic enforcement. These rules were published on January 14, 2025.
Key Provisions of the New Rules
The rules introduce a new “Part X” to the Eighth Schedule of the Legal Metrology (General) Rules, 2011, detailing requirements for “Radar Equipment for Measuring Speed of Vehicles.” These provisions cover:
Correct Operation
- Radars must be used according to approved instructions.
- The equipment must accurately identify the target vehicle, even in complex traffic situations like overtaking or when the radar is moving. Direction discriminators and other devices are required to ensure accuracy.
- Aiming devices are necessary to control the angle of incidence and minimize measurement errors. Specific angle ranges are mandated.
- Antenna radiation patterns must be controlled to prevent inaccurate measurements due to incorrect angles.
- The time span for speed indication must be sufficient for observation, and further measurements should be inhibited until cleared.
- If recording devices are used, they must record date, time, measured speed, vehicle direction, and radar sensitivity.
- Specific requirements are outlined for automatic and autonomous radar systems operating without continuous operator supervision.
- Speed indications must be automatically inhibited when power voltage fluctuations could lead to errors.
- Radars must have built-in self-testing mechanisms to verify proper functioning.
Construction
- Indicators must be easily readable.
- The radar must be robust and built to withstand various conditions.
- The equipment must be resistant to extreme temperatures (-25°C to +70°C for storage, 0°C to +50°C for operation) and humidity.
- Weather-exposed parts must be dustproof and splashproof.
- Electronic components must be reliable and protected against disturbances like power line variations and electromagnetic fields. Specific testing criteria are outlined in Annexure A.
Manufacturers must provide detailed operating instructions covering theory, schematics, operating conditions, modes of operation, potential error sources, and the influence of various factors on measurements.
All parts that could be tampered with to affect measurement accuracy must be sealed or protected.
Each unit must be clearly marked with manufacturer information, type, serial number, and connecting unit details.
Model Approval
Rigorous laboratory and field tests are required for model approval, covering temperature, humidity, power voltage, microwave section performance, low-frequency section accuracy, and discrimination capabilities.
Specific error limits are defined for various test conditions. Tests for the effects of influence factors and disturbances are detailed in Annexure A. Field tests in real traffic conditions are mandatory.
Comparison measurements must be made against a highly accurate reference system. Manufacturers must submit details of the instrument’s logic, and any changes require approval.
These comprehensive rules are expected to:
- Improve accuracy and reliability of radar-based speed enforcement.
- Ensure fairness and transparency in speed measurement.
- Provide clear guidelines for manufacturers, operators, and regulatory authorities.
- Enhance road safety by promoting accurate speed enforcement.
The detailed technical specifications and testing requirements outlined in the rules and Annexure A demonstrate a strong focus on ensuring the metrological integrity of radar speed measurement devices.
