A flexible approach to select road traffic counting locations: System design and application of a fuzzy Delphi analytic hierarchy process

Although the diffusion of Information and Communication Technologies provided transportation analysists with new data sources (such as Floating Car and mobile devices), the use of permanent sensors installed on roads is still of paramount importance for traffic analysis. Continuous count stations are one of the main components of a road traffic monitoring program, which could fulfil several aims: (1) planning of a transportation system, (2) traffic management and operations, (3) improvement of road safety, (4) special monitoring for planned/emergency events, and (5) estimation of environmental impacts. In this research activity a Fuzzy Delphi Analytic Hierarchy Process (FDAHP) was applied to select the best locations for a fixed number of permanent count stations, as the basis of a traffic monitoring program that can reach the previously described targets. A real case study was developed in the Città Metropolitana di Venezia (Italy), where budget limitations imposed the need for a scientific and sound framework to decide where new sensors should be installed. Specific objectives and criteria were defined, as well as proper indicators to quantify them using available data. Their relative importance was evaluated by a panel of experts belonging to several agencies, therefore with different perspectives. The information obtained was analysed following the FDAHP approach to produce a ranking of the potential locations. The proposed holistic approach can be considered as a reference framework for a system to support local authorities in creating a traffic monitoring system and can be easily applied to other study areas.