Managing the Noise in Our Lives by Gabriella Cerrato

A few weeks ago, I reported on a Newsweek article on the "roar of the 21st century" and its effect on our lives. In the Summer 2005 issue of Intelligent Life, a publication from The Economist, this subject is again discussed in an article titled "The Sound of Silence." Two non-scientific publications discuss noise as an important social and cultural factor in our lives. This is not a coincidence.

Just looking at published references, it seems to me that 20, 30 years ago, the main focus in the noise and vibration community was in reducing and managing the noise in the workplace. While this is still an important objective, today an equally large effort is dedicated to the management of noise in our life outside of the workplace, at home, at play and on the road. As the article in Intelligent Life points out, noise annoys, especially when we do not control it. The throaty sound of Eric Frank's motorcycle (see previous post) is certainly symphony to his ears, likely not to his neighbors'. The new millennium has brought many social, political and financial uncertainties, and at least at home we want, and need, to feel in control. Noise is something we can control and governments and federal organizations should help us to do so.

Ground vehicles are significant sources of environmental noise. What do governments do in order to regulate the exterior noise from vehicles? Broadly speaking, there are two main groups of vehicle noise regulating standards: for passenger vehicles and trucks and for outdoor machinery (lawmowers, tractors, etc.). Let's discuss passenger vehicles and light trucks. Motor vehicle noise is measured according to various standards, ISO 362 being one (ISO stands for International Organization for Standardization). These procedures entail measuring the noise emitted (generally speaking, dB(A)) by a vehicle as it accelerates through a predefined area of a test track designed for this purpose. In order to normalize vehicle operating conditions (and thus level the playing field measurement-wise) there are stipulations within these specifications as to the allowable engine speeds and gears during the test. The measured noise has to be less than a certain value as called out in the specifications. Efforts are ongoing to ensure that the test methods in the ISO 362 reflect noise emission conditions in real life.

Since this is a very important topic that we have not yet discussed, I have asked Doug Moore, who is Lead Engineer for Exterior Noise at General Motors Corporation, to explain how the ISO 362 is evolving and what are the industry and government trends in this area. In the next post, he will give us a summary of the important work being done by international organizations and vehicle manufacturers across the globe to improve the current legislation.