Development of Forecast Functions for the Road Conditions of Municipal Roads



Dirk Kemper © Copyright: ISAC


Dirk Kemper



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  Diagram: Exponential increase in road damage Copyright: © ISAC

The road body is continuously stressed by traffic, climatic and structural influences. These cause permanent wear and can ultimately result in the destruction of the road infrastructure. The restoration of the road body and thus the preservation of traffic safety and driving comfort require high investments on the part of the respective road authorities. Depending on the situation, these are divided into the areas of responsibility of the federal government, the states or the municipalities.

With the funds available, investments in road maintenance must be spent as selectively and effectively as possible. If possible, this should not be done after the road has finally lost its function. Therefore, it is of great advantage to know how much money has to be spent at what time and where. A systematic maintenance management system forms the basis for this. The core of such a system consists of both condition data collected from surveys and their evaluation as well as scientifically created forecast functions. These allow reliable statements to be made about the development of the road condition. Future interventions in the road infrastructure can be read from the functions and directly integrated into the temporal and local planning of measures.

Within the cities, however, there is little knowledge available to draw up meaningful condition forecasts for inner-city roads. The reason for this is the higher complexity of these road types, both in terms of construction and use. Additional challenges arise in this context. In addition to the higher variety of superstructure types and pavements, there are highly inhomogeneous conditions in the subsoil. These are manifested in existing shafts, ancillary facilities and structures, some of which have grown historically. Furthermore, extended traffic types such as bicycles and public transport put additional strain on the road body. The road network in cities differs significantly in structure from, for example, highway networks. Therefore, the functions already existing and applicable for extra-urban roads cannot be easily transferred for intra-urban roads.

Different functions of the inner-city traffic space, which allows both flowing traffic and standing or parked traffic, determine the above-ground conditions. For various reasons, different pavements and types of construction are used for the different types of use, and the linkage at the interfaces must also be accomplished in terms of construction technology. Thus, the road space can reflect a varying image of bituminous, pavement and concrete surfaces. A large number of lines from various supply and disposal companies as well as other line carriers of different media are laid under the road surface. The high mass of parties involved also requires careful coordination of necessary breakups of individual road sections in order to save resources and costs. These condition indicators must also be taken into account in the form of prognosis functions for municipal roads, as must the traffic load on the entire road structure.

The primary objective of this research project is to develop prognostic functions for urban road conditions. The above-mentioned influences and the resulting effects on the inner-city road network are to be recorded, reflected and summarized in an appropriate and correct manner for municipal maintenance management. The recorded condition data in the context of an extra-local maintenance management are to be restructured if possible in such a way that the quantity of the data and likewise their interpretation and evaluation are adapted to the new boundary conditions. The need for the types of data to be determined for the roads is to be determined as a matter of priority. Based on this, a homogeneous delimitation and definition of the routes with regard to the user behavior and the road structure is to be carried out, comparable to extra-urban roads.

  Diagram: Road damages Copyright: © ISAC