As a result of the national speed reduction, the noise level only decreases during the day. In the evening and night the speeds do not change and therefore the noise level will not decrease in those hours. This variation is mainly determined by the share of freight traffic. With a low percentage of freight traffic, the decrease in noise levels during the day is greater than with a high percentage of freight traffic.
The amount of noise that the environment may experience from national roads and from other environmental noise is expressed in the European measure for noise exposure Lden (English for Level day-evening-night). It is a measure of the average sound level over a XNUMX-hour period, whereby the noise in the evening and night periods counts more heavily than the noise during the day. This is because noise at night is much more annoying than noise during the day.
Rijkswaterstaat monitors noise production along national highways every year. The Compliance Report Noise Production Ceilings contains the results of this monitoring and the steps taken to comply with noise production ceilings. When the current noise production has approached the ceiling at 0,5 dB and it is expected that the ceiling will be reached within five years, Rijkswaterstaat describes which steps are being taken to prevent exceeding the noise production ceiling.
speed reduction gives a two-year delay
The monitoring shows that as a result of the growth in car traffic, noise production increases - on average across the country - by 0,1 dB annually. Due to the national speed reduction, depending on the location, it may take 1 to 2 years longer before the moment is reached that measures must be investigated to prevent a ceiling being exceeded.
Since noise nuisance is subjective, it will differ per person how this decrease is experienced. That is why it is in line with the method included in the European Environmental Noise Directive. This guideline prescribes that the number of (severely) noise-affected persons and sleep disturbances must be reported every five years.
This number is determined on the basis of the noise exposure of their home (XNUMX-hour average value Lden and the night-time noise level Lnight, respectively). The higher the noise pollution of their home, the more noise nuisance residents will experience. This is based on a dose-effect relationship that indicates the percentage of residents who are (severely) hindered or sleep-disturbed under a certain noise level.
Also read: Speed from March 16 100 km per hour on all highways
