STUDIES OF MOTOR VEHICLE NOISE. SUPPLEMENTARY STUDIES OF MOTORCYCLE NOISE ACCORDING TO THE FRENCH PROPOSAL R/1512/77 (ECO 172). SUPPLEMENTARY STUDY OF THE NOISE OF SMALL MOTORISED BICYCLES (MOPEDS) ACCORDING TO GERMAN AND DUTCH SPECIFICATIONS

1. UNTERSUCHUNGEN UEBER DAS GERAEUSCHVERHALTEN VON KRAFTFAHRZEUGEN. - 2. ERGAENZUNGSUNTERSUCHUNGEN UEBER GERAEUSCHMESSUNGEN AN MOTORISIERTEN ZWEIRAEDERN NACH DEM FRANZOESISCHEN VORSCHLAG R/1512/77 (ECO 172). - 3. ERGAENZUNGSUNTERSUCHUNG DES GERAEUSCHVERHALTENS VON KLEINKRAFTRAEDERN (MOFA UND MOPED) NACH DEUTSCHEN UND HOLLAENDISCHEN VORSCHRIFTEN

IN CURRENTLY VALID RECOMMENDATIONS DRIVING NOISE IS MEASURED AT FULL ACCELERATION. SINCE HIGH-POWERED CARS REACH A HIGH NUMBER OF REVOLUTIONS AND SPEEDS, THEIR MEASURED NOISE VALUES ARE HIGHER THAN THOSE OF LESS POWERFUL CARS. THIS MEANS THAT IF THERE IS A FURTHER REDUCTION IN PERMITTED NOISE LEVEL VALUES, HIGH POWERED CARS WILL BE THE FIRST AFFECTED, ALTHOUGH IN PRACTICE IN URBAN DRIVING ONLY A SMALL PROPORTION OF THEIR POTENTIAL POWER IS USED. CURRENTLY VARIOUS PROPOSALS FOR A DIFFERENT MEASURING PROCEDURE ARE BEING DISCUSSED INTERNATIONALLY. THE VARIOUS PROPOSALS ARE BEING TESTED BY MEASUREMENTS ON 58 CARS, AND THEIR ADVANTAGES AND DRAWBACKS EXAMINED. BASED ON THE RESULTS, A PROCEDURE IS TO BE PROPOSED WHICH SHOULD BE AN OPTIMUM COMPROMISE BETWEEN COST AND ACCURACY. THE FRENCH RECOMMENDATION R/1512/77 (ECO 172) IS TO BE TRIED OUT, AS IS THE DUTCH PROCEDURE FOR SMALL MOTORIZED BICYCLES HAVING A LIMITED MAXIMUM SPEED.