The "Amsterdam noise
measurement apparatus"
Road-side noise measurement is carried out while the motorcycle is stationary and the engine is running at a specified rpm The result is compared with those of the same test carried out during type approval. A complete description of the test is contained in Directive 97/24/EC Chapter 9 (see Annex). Several problems prevent the police or other law enforcement agencies carrying out road-side noise measurements on a large scale. Manpower To perform the test, the following tasks have to be done at the same time:
This requires at least two and preferably three policemen The use of both the sound-level meter and the rpm meter requires specialist knowledge/training, not currently available to the average policeman. Compared to speed-cameras the requirements are a large commitment for the enforcement agencies. The rpm meter The engine has to run at a defined rpm; not every motorcycle is equipped with a rpm meter. Besides this practical problem, there is a legal problem. Courts in the Netherlands have decided that the police cannot use the rpm meter of the motorcycle as this meter is not officially calibrated. The use of a portable rpm meter using the ignition signal can give problems with some types of ignition which do not have clear "pulses". Additional problems of access are encountered when the engine is covered by a fairing. The operation of the throttle In court, riders have successfully managed to dispute the operation of the throttle during the test, as it was impossible to that it was done in accordance with the Directive. Description When the Court made it impossible to continue with the old way of sound-level measurement, the police were obliged to find a solution. The Amsterdam police asked the company KOVA Techniek B.V. to develop an apparatus such that the result could not be disputed. The development was subsidised by the Netherlands Ministry for the Environment. The result is a single box which integrates a sound-level meter, a rpm meter and a processor. The processor ensures that the measurement procedure is properly followed and excludes any human error. Firstly, the rpm level corresponding to the model of motorcycle to be tested is entered into the processor. A telematic receiver next to the motorcycle feeds the rpm meter with a signal. The owner of the motorcycle operates the motorcycle himself following the indications given by the lights on the Apparatus. (The lights on the Apparatus indicate when to open, close or keep the throttle steady). Before and after each measurement the ambient sound-level is checked. Once a sufficient number of valid measurements have been taken, a printout can be made with the individual measurements and the final result (Page 6). Advantages The processor rejects any false measurements and ensures that the complete procedure as described in the Directive is followed. A single policemen can catty out the complete operation. Particular knowledge of sound-level meters or rpm meter's not necessary. The final result is an error-proof measurement and the absence of any dispute. Thanks to the print-out the test result is accepted more easily by the rider and this is a psychological advantage for the policeman. The immediate print-out may offer the possibility of "on the spot" fines, reducing the administrative workload for the police and the court. This is a more general issue for the legal authorities to consider.
The rpm-value at which the sound-level has to be measured and the reference sound-level are not always easily available. Although the Netherlands police have direct access to the type-approval database of the Registration Authority, very old registrations (pre 1st October 1980), parallel imports, and foreign registrations are not recorded. The impact of a roadside measurement campaign can be greatly increased by using high-profile press coverage. At the national motor-show, the police give all visitors the opportunity to check their motorcycles free and without any consequences. This is usually done in front of the entrance, and covered by the TV and press. From this, most of the riders understand that noise is a serious item for the police. Later in the year, at places where a lot of motorcyclists and also a lot of motorcycle noise is expected, the police measure every motorcycle passing by with apparently too much noise. This is done during the whole day with so many policemen that no motorcyclist can escape. The results of the action are sent to the newspapers. These repeated reports of police actions help "noisy riders" to understand that noise is not only a serious item for the police, but will also be a serious problem for them if they don’t do something about it.
 The print-out of the results
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