Multi criteria analyses for managing motorway company facilities: The decision support system SINERGIE

Improvements to the decision‐making process in the areas of preventive maintenance and facility repairs for a range of infrastructure include maintenance, upgrading and retrofitting operations. Depending on the available information concerning the condition of the facilities, specific types of projects can be programmed. Assigning a priority of action to a given project necessitates an evaluation process that introduces several criteria at various functional levels. This multi criteria (MC) evaluation is modelled as the aggregation of partial scores attributed to a project with regards to (w.r.t.) a given set of criteria. The scores are expressed over a finite scale which can cause some troubles when no attention is paid to the aggregation procedure. This paper deals with the consistency of the evaluation process, where scores are expressed as labels by experts (over finite discrete scales), whereas the aggregation model is supposed to deal with numerical values and cardinal scales. This is a curious but common apparent paradox in MC evaluation when engineering contexts are concerned. Adequate mathematical tools are provided to tackle the related problems. A robustness analysis of the evaluation process concludes the mathematical part of the paper. The mathematical choices regarding our information processing chain meet the ESCOTA motorway company requirements. Indeed, ESCOTA aims at the formalization and improvement of the decisional process for preventive maintenance of its assets in a MC framework. According to available pieces of knowledge on the infrastructure condition, projects are to be evaluated w.r.t. technical but also to conformity, security and financial criteria for planning purposes. ESCOTA’s engineers are used to manipulate symbolic labels but might convert them into more or less arbitrary numerical values when necessary without the necessary care. The SINERGIE decision support system has been developed for ESCOTA to implement a logically sound information processing methodology. The SINERGIE man–machine interfaces illustrate the way by which the mathematical concepts described in this paper are used in terms of infrastructure management activities. The various information processing phases laid out in SINERGIE have been illustrated for road applications.