PLANNING INDICATIONS
7.1.4 Traffic volume and traffic calming

The traffic volume has a big influence on noise pollution (see section 3.1.2.4, fig. 3/2). A doubling of the volume increases the noise level by 3 dB, while a halving reduces it by 3 dB. The percentage of trucks also contributes significantly to the production of noise. Noise pollution can therefore be reduced by reducing the traffic volume, especially the number of trucks. In inner city traffic, about twenty passenger cars are as loud as one truck, on motorways this ratio is about 5 to 1 (LAI Indications on Noise Abatement Planning 2012, p. 20).

The traffic volume can be reduced for example through pedestrian-friendly city planning (attractive footpaths off major roads if possible, wide pavements, pedestrian zones), a large-scale cycleway network and an attractive public transport system. Traffic in areas requiring protection can also be reduced by adequate parking space regulations and by providing conveniently arranged parking possibilities. The creation of park-and-ride sites for example should be considered during planning in order to induce commuters to use the local public transport system (trains, low-noise buses). Traffic within residential quarters can largely be avoided by establishing central (underground) parking lots. Adequate areas should already be designated in the planning stage.

The traffic volume can also be reduced in the context of traffic calming measures by modifying the development of residential areas. Development roads must not submit through traffic, which can be directed on major roads through zones requiring less protection. Figure 7/5 gives an example of traffic calming through inner development in the building area "Auf der Steig/Daiberweg" in Stuttgart-Bad-Cannstatt.

The additional noise pollution at a major road going past a residential area is low compared to a through road leading through the residential area. The degree of noise reduction in the calmed residential area, however, is higher.

This can be illustrated by a simple example: If the residential area is not calmed, 1,500 vehicles per hour will travel on a major road outside the residential area. 800 vehicles will use the through road through the residential area. If the residential area is calmed, about 2,100 will be expected to use the major road and about 200 the development road within the residential area. In this case, the noise level at the major road will be expected to increase by about 1.5 dB while the noise level in the residential area will be reduced by about 6 dB.

With regard to a reduction of the traffic volume, roads must be dimensioned in a way that they do not attract additional traffic.

In any case, planning should provide for the shortest possible distances between different uses.

Many car trips can be prevented and therefore the traffic volume reduced by reducing the distances between dwellings, businesses and workplaces (e.g. a supermarket should not be established in the green countryside).

Traffic bans and traffic restrictions (fig. 7/6) can also help to reduce noise. This can be useful in the case of nighttime driving bans in areas requiring special protection (hospitals, health resorts) or transit bans for trucks on certain road sections.

The transit of especially noise-intensive trucks through the residential quarters of towns and cities can be reduced by considering the possibility of transferring the transportation of goods to trains already in the planning stage. The necessary sidings and places for transshipment points must be designated and industry with rail-oriented products located in these areas. Rail links can be particularly worthwhile for manufacturing industries or waste management companies. Commercial areas should at least be located in a way that the connection to the supra-local road network is direct and short without affecting residential uses.