Traffic-related bulk deposition in roadside areas
The emissions from road traffic and the winter road maintenance result in pollutants and de-icing salt being deposited in roadside areas. A major part of this collects on the road verge and the edge of the roadway and then - depending on the type of drainage with the road run-off - gets on and into the nearby soil. This process, stretching over decades, results in high accumulations of heavy metals forming in soils adjacent to the roadways of roads subject to heavy traffic. High concentrations (relative to the environment) of organic substances, such as PAHs, are also present.
Sampling road run-off water
The BASt undertakes sampling and analyses of impurities in the road run-off water and dust precipitation at three locations on federal motorways for the purpose of investigating the changes over space and time of the deposits in the soil and drainage facilities as well as the quantity of pollutants transported with the leachate. In this manner, it is intended to create baseline information to measure road verges and drainage facilities in relation to pollution retention as well as identify starting points for mitigation measures and their success control.
Sets of rules
The results are required for creating and revising sets of rules for planning, construction and operation of roads (Building of roads guideline – section on UVP, Building of roads guideline – section on drainage (RAS Ew), Building measures on roads in water protection areas guideline (RiStWag), Road verge material guideline, information on controlling drainage facilities) as well as other rules regarding the use of extractive waste in road building. Accompanying this, further topics relating to bulk deposition resulting from road traffic are handled in internal and external research projects, including tyre abrasion as a source of substance deposit or the depositing of nitrogen compounds in sensitive biotopes caused by road traffic.