Approx. 3000 street management authorities of Switzerland lack a uniform statement to proof the annual need of funding for maintenance according to economic points of view.
The proposed statement shall allow the determination of value consumption by simple means also for non-specialists; but at the same time it shall be open for deeper scientific approaches and optional extension to other infrastructure than streets.
The project aims to answer the following research questions:
- According to which categories of roads should road management authorities invent their respective road systems in practice?
- What are the replacement values of the paving works of each street category?
- What are the actual practical life spans of the individual parts of the paving construction of each road category?
- What are the margins between which the proposed statement can be applied?
As a rule the existing approaches for quantifying the funds needed annually are based on a bottom-up approach. Investigations of condition are performed and, on the basis of these investigations, maintenance programs are calculated for a period of up to a maximum of ten years. In order to quantify the funds needed from a network-wide point of view (top-down approach) it is being postulated that the long term average of funds needed for maintenance of the road infrastructure in order for it to be maintained in the long term should be roughly the same as the annual average deterioration. Important in this context is the complementary view of these two approaches.
The method for determining the deterioration shown in this research report was primarily developed for road networks in local communities. The model is based on a deterioration formula whose dependent variables are the replacement value and the ageing coefficient. All the roads in a community are categorised and replacement values and ageing coefficients are set for each category. The chosen procedure is based on a few specific values of a representative community road network and is simple and transparent in its application. The model is also configured in such a way that, if applicable, specific requirements of the community can also be considered in a transparent and comprehensible way. The principles used by the model could also be adopted for other road networks (e.g. district-wide) provided the corresponding parameters for the model were available.
This research project deals with a method for estimating the funds needed for the maintenance of road networks in communities and shows how the annual average deterioration (of value) can be estimated from a network-wide point of view. The research project is based on the city of Zurich's standard conservation of value model.
The research work is limited to the road superstructure and the associated infrastructure such as kerbs, drainage, illumination and, if applicable, the road layout. Aspects not covered in this work are special structures such as tunnels, bridges and retaining walls together with general technical equipment and other infrastructure items.
"VSS erforscht Instrument für einheitliche Kennzahlen beim Mittelbedarf"; Strasse und Verkehr Nr. 4 April 2004
Forschungsbericht zum VSS Forschungsauftrag 2002/703 " Durchschnittlicher jährlicher Wertverlust von kommunalen Strassennetzen aus einer Netzsicht"; ASTRA, 2005