Which signage is necessary to secure a construction site is determined on the basis of the particular local and traffic circumstances in each individual case.
Of particular importance is the correct exercise of discretion by the road traffic authority or the road construction authority. Their orders regarding the setting up and securing of roadwork sites by means of signage must above all be measured against the principle of proportionality. This applies to the safety measures as well as to the (traffic) burden on third parties caused by the construction site.
Among other things, the interests of residents who are particularly dependent on the use of the road must be included in the consideration. This applies above all when commercial operations are affected. Work sites are therefore to be planned by the entrepreneur in such a way that their duration and spatial extension impede the traffic flow as little as possible. If the road space is temporarily not necessary for the construction site or if the circumstances allow temporary facilitation of traffic, then this must be taken into account. Wherever possible, work on busy roads should be carried out during off-peak periods.
In the case of spatially longer work sites, care must be taken to ensure that - in accordance with the progress of construction work - the length and width of the work site that is effective for traffic is kept as small as possible. For the design of the necessary signage and the coordination of further measures, the road traffic authorities are assisted by the nationwide guidelines for securing work sites on roads. These include standard plans for construction sites on local roads, rural roads and highways.
Information is available from the road traffic authorities at the district offices, independent cities and municipalities.