Silence Is Golden at the Michelin Challenge Bibendum-The Quietest Vehicles Set the Best Scores in Noise Level Competition

FONTANA, Calif., Oct. 27 -- Day two of the Michelin Challenge Bibendum 2001 got under way today with the noise emissions test. Participants, monitored by special microphones, were competing to be ... silent.

Normally, the California Speedway plays host to ear-splitting competition that has motors racing in a rapid rise and decline of decibels as vehicle engines sprint past the grandstands in a Doppler effect of ZoooooOOOoooooom! But today's opening event in the Challenge was just the opposite.

``Noise is an ever increasing problem in our cities and towns,'' said Ron Musgnug, project leader of the Michelin Challenge Bibendum 2001. ``This has been recognized for some time in Europe, where the European Union has defined standards and goals for reducing external vehicle noise levels since 1970.''

As with all events at the Michelin Challenge Bibendum 2001, participants compete against predetermined performance thresholds, not against each other. The noise competition is based on standard ISO 362 and is reported in decibels (dB). Those scoring in the A category were the quietest. For more on the how the noise testing was conducted and scored, visit our web site at http://www.challengebibendum.com or, take a moment now to ...

Ask Bibendum about the noise test

Q. What is ``noise''?

A. Webster's New World Dictionary defines noise as ``any loud, discordant, or disagreeable sound or sounds.'' Ambient noise is defined as, ``constantly and spontaneously occurring background noise.'' Passing traffic typically produces ambient noise. As a frame of reference, the noise level of a busy restaurant is about 80 dB whereas the noise level of a quiet conversation is about 66dB.

Q. What creates vehicle noise?

A. Automobiles generate noise in two ways: One, vibrations produced by the mechanical parts of the vehicle. It originates from the engine, gears and air flowing through the air manifold to the exhaust. Two, external noise, from air turbulence created by the vehicle as it moves, and tire/road surface contact.

Q. When did noise become a problem?

A. Even in the 19th century, the noise of clopping horseshoes and iron carriage wheels on stone streets rattled the nerves of city dwellers. As iron carriage wheels came to be replaced by those clad in rubber, there was a noticeable reduction in the clatter. But then something else came on the scene: Enter the automobile. It was not long before the first cars, with noisy engines and honking horns, began to clog American and European city streets. By 1950, some small efforts were under way to limit the noise a car horn could make and in 1970, the European standard for vehicle noise was set at 82 dB. Today, the current European standard is 74 dB. When the next standard goes into effect, it will be set at 71 dB.

Q. Is noise a nuisance or a serious threat?

A. It depends who you ask. Some experts say that, in addition to damaging hearing, regular exposure to noise levels above 85 dB can result in high blood pressure and cardiovascular disease.

Q. For the Michelin Challenge Bibendum, what noise is being measured?

A. The noise test evaluates the noise level of the passing vehicle during acceleration, as people outside the car would perceive it.

Q. How is the noise level of the vehicles measured?

A. Each vehicle arrives in the measurement zone, traveling at a speed of 31 mph, +/- 0.5. (or about 50 kpm, +/- 1) and accelerates to wide open throttle. While in the measurement zone, the vehicle passes between two microphones placed at the side of the test track. These microphones measure the sound level as the vehicles pass between them. The maximum sound level obtained during the passage of the vehicle is recorded for each microphone and the result of the run is the average value in decibels. For scoring, vehicles will be allowed a maximum of three runs, the two best runs will be averaged to obtain the vehicle's score. Failure to achieve two valid runs out of three will result in a ``no score'' grade.