Vehicle Pass-by Noise

The external sound of a moving vehicle is part of its character and can be an essential part of its appeal. But the collective traffic noise from thousands of cars and trucks can be considerable. To help reduce noise in our environment, government agencies set pass-by noise limits for each type of ground vehicle – critical regulations that must be respected.

Acoustic Characterization

Characterizing the overall acoustic signature of a vehicle requires measuring it while in operation as it passes by stationary microphones. Measurement standards stipulate how the vehicle must be driven, both at constant speed and under acceleration, when passing through the test area. They also define the road surface and weather conditions that must exist for a valid measurement.

Pass-by Noise Standards

Pass-by noise measurement is mandatory for automotive manufacturers for type approval and conformity of production.

The measurement procedures and conditions are defined by international standard ISO 362, whilst the accepted noise emissions are stipulated in UN regulations.

• R51 for most types of vehicle from passenger cars to heavy commercial vehicles 
• R41 for two and three-wheeler vehicles 

In some countries, local regulations may also be in force, but all follow the same general procedure for testing. In addition, pass-by noise measurements can be used for product development and troubleshooting.

Since pass-by testing is an intensely standardized area, it is important to stay abreast of the latest developments. Our software helps guide you through all of the required testing steps for the relevant standards, ensuring that mandatory information is logged, the measurements are performed within the required operating limits, and the correct calculations are performed to produce the final result.

Indoor Test Standards

For many years, indoor testing has been used to support vehicle pass-by noise, both in product development and problem troubleshooting. ISO 362-3 describes the procedure and the required equipment.

In 2019, R51 Annex 7 added the indoor method for type approval. Consequently, our software was updated to simplify the process of indoor pass-by measurements for regulatory testing with the emphasis on ease of setup and simplicity of compliance.

Pass-by Testing Solutions

The data-centric pass-by solution enables an optimised workflow with the full capability of combining the data of indoor and outdoor pass-by measurements via the Team Server – a shared data storage system.

Learn more about our solutions for vehicle pass-by noise testing:

Related Information

• Indoor Pass-by: A solution to an Outdoor Problem
• Pass-by Noise Regulations – Meet the Latest Indoor Standards