In acoustic terms, it is advantageous to plan the route of e.g. bypasses and railways as far away from uses requiring protection as possible. This also means that uses requiring protection, e.g. residential areas, must not come close to existing bypasses (fig. 6/1g). A doubling of the distance between the two uses leads to a level reduction of 3 to 4 dB (see fig. 3/6 in section 3.1.2.2). This shows that the displacement of the routing has only minor effects with an increasing distance between transport route and place of immission.

Wherever possible roads shall be planned and constructed in a way that traffic can move slowly and uniformly. Roundabouts (fig. 6/1h) are to be preferred to normal crossings in this context. Rapid sound level increases through braking or starting vehicles (see section 6.2.1.5) cause particular disturbances. This is why RLS-90 considers the nuisance factor of crossings with sound level additions of up to 3 dB when determining the rating level.

Slopes also have negative effects on the noise level. The lower the gradient, the lower the noise pollution.

As mentioned before, the concentration of transport routes (fig. 6/1i) is advantageous in acoustic terms (noise goes well with noise). Existing noise sources shall therefore be taken into account in the planning of roads and railways. The path of future transport routes is best aligned along existing sound sources, e.g. a road along existing railways. Noise exposure in the area of the existing transport route is mostly only slightly increased and areas not exposed to noise remain quiet.

Planners should consider topographic elements which are favourable in acoustic terms, e.g. indented positions, when selecting the route.

In the context of the construction of bypasses, the affected population must further be relieved from noise exposure through traffic calming measures (fig. 6/1j) and the renaturation of existing through roads.

An adequate and sufficient curve radius must be considered along the course of railway lines. Narrow curves lead to squeaking noises and to sound level increases of up to 8 dB.

Curve radius and gradient of the route should be favourable for the tram dynamics and permit high speeds. But the speeds on the individual track sections should be adapted to the type of use of the area along the tracks and the individual urban development situation. Standalone tracks should have a curve radius and continuous tracks that allow for the use of the maximum speed in track curves.