What's the point of a speed limit?
In Germany, the benefits of a general speed limit on motorways are discussed again and again. This would probably result in fewer road deaths and reduce emissions of carbon dioxide and particulate matter. But the data is open to interpretation, and the effects may be smaller than many think.
Does the German Road Traffic Act need an amendment that sets a maximum speed on motorways? The debate on the topic quickly becomes emotional and is difficult to conduct for that reason alone. But it also suffers from a lack of current data and studies from Germany on what such a restriction could do. External help is hardly to be expected: All neighboring countries have had speed limits on their motorways for a long time. At most, they talk and research whether to relax or further tighten the limitations.
Here in this country, two important investigations come from the years 1999 and 2007 and are based on even older data. Interpretations, plausibility considerations, estimates and extrapolations are therefore just as important and present in the discussion as numbers. In the search for answers to questions about the speed limit on motorways, you have to cut a path through the jungle and yet you always run the risk that in the end both sides will see their position confirmed by a clever choice of arguments.
On the question of whether a speed limit benefits the climate, there is only one relevant study in Germany. It was created in 1999 by the Federal Environment Agency (UBA) and is based on data from 1992. At that time, cars drove an average of 120, and 15 percent of cars had a speed of more than 148 kilometers per hour. In the meantime, an investigation by the Federal Highway Research Institute has made it known that between 2010 and 2104 not much had changed in these driving data…