Acoustic properties of road markings
Road markings are an important part of a safe road. Regularly driving over markings can lead to noise nuisance for local residents, especially with quiet road surfaces. How can the noise emissions caused by vehicles crossing markings be measured and assessed?
Driving over profiled road markings is increasingly leading to complaints from local residents. Road markings are regularly driven over unnoticed. On motorways, this happens when changing lanes, crossing a side line, at an entrance and exit, or when leaving the motorway. On provincial and inner-city roads, this happens, for example, with speed and direction information on the road surface, when crossing the margin in narrow lanes, or to accentuate the boundary of a crossing with cross markings. The noise of driving over road markings leads to complaints because increasingly quieter road surfaces have been used in recent years. The difference in noise level between driving on the road surface and on the marking has increased, making the noise of the markings more noticeable.
Noise requirement of road markings on national motorways
In 2015, we carried out a study commissioned by Rijkswaterstaat into the acoustic properties of various types of marking that are used on national roads. Based on this, Rijkswaterstaat drew up a noise requirement for road markings since October 2018.
The purpose of this requirement is to prevent noise nuisance for local residents. This requirement includes a limit value of 5 dB (A) between the noise level when driving on the marking and driving on the road surface on which the marking is applied. In order to be able to test this, a measuring method is applied that has been drawn up in a European context (CEN working group). This method is based on the CPX method (ISO 11819-2), which uses a CPX trailer to measure noise both on the marking and on the road surface.
Since the 2015 survey, we have measured road markings at many locations using our CoMeT CPX system, including measuring the height of the marking using our FLaSH|M laser texture system. The noise emitted when driving over the marking is determined, among other things, by the geometry (height and shape) of the marking, type of material, and the road surface on which the marking is applied. Thanks to smart geometry adjustments, noise emissions can be reduced when driving over markings. We will be happy to work with you.
An example of innovative marking in which we are involved is a pilot on the N502 in the municipality of Schagen.