An Evaluation of Test Procedures for Vehicle Exterior Noise

There has been much discussion recently in Europe and the USA of test procedures for the measurement of vehicle drive-by noise for legislative purposes. A program was therefore undertaken to evaluate a number of these procedures for both light and heavy vehicles.

A special instrumentation system was developed for this project which, whilst not essential for routine development testing, was of considerable value for research purposes and for monitoring type approval and production conformity tests. Detailed records of the vehicle operating conditions and position during the tests gave a much more thorough understanding than has been possible hitherto.

Two new test procedures are proposed. One is a drive-by test which reproduces similar operating conditions to ISO R362, but without the anomalies inherent in that procedure. The second is a stationary test that will give good correlation with the drive-by test and can be used for development, production conformity and enforcement testing.