In urban traffic, cars with electric engines are not only cleaner but also less noisy than cars with internal combustion engines. In particular this applies for speeds up to 20 kilometres per hour. A fully electrified fleet will be 3 to 4 dB more silent compared to the present fleet. The number of people severely annoyed by traffic noise will be reduced by one third. However, it will last at least until 2030 before there are enough electric cars to realize this noise reduction. Compared to hybrid cars, that use both an internal combustion engine and an electric engine, fully electrified cars are 1 to 2 decibels more quiet. At speeds above 50 kilometres per hour, electric and hybrid cars are not quieter than conventional cars. This is because the tire-road noise increases with speed and becomes the dominant noise source. Silent cars may lead to increased traffic safety risks, especially to the blind and visually-impaired. Because hybrid or electric cars are less likely to be noticed in traffic, they may pose danger. In the United States of America an analysis of crash records has shown that hybrid cars are involved relatively more often in crashes with pedestrians and bicyclists than do conventional cars. This only occurs in situations where the driving speed is low, such as backing up and parking manoeuvres. Up to now, analysis of traffic accidents in Japan and the Netherlands has not shown increased risks for silent hybrid cars. In the United States and Japan, minimum noise requirements are now being considered. Slowly driving silent cars would then have to produce warning sounds continuously. If minimum noise levels will become compulsory for the European car market, the prospects of less noise annoyance are restricted. (Author/publisher)
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