Accessibility of municipalities to major transport infrastructures

Within the framework agreement between Istat and Managing Authority of PON “Governance and Institutional Capacity 2014-2020” for “Territorial and Sectoral Statistical Information for Cohesion Policy 2014-2020”, Istat publishes new statistical indicators at municipal level on accessibility to infrastructure nodes related to four types of transport networks: road, rail, sea and air.

The study of accessibility is closely linked to issues of territorial peripherality and marginality, concepts that are fundamental to public policy strategies and to spatial planning. Citizen’s quality of life, as well as competitiveness and productivity of businesses, are significantly affected by the ease or difficulty of access to infrastructures.

Accessibility can be approached from different perspectives. The general concept that links all the different measurements is: the easier it is getting to a location, the more accessible the location. This means that distance between origin and destination, which also reflects travel costs, is the basic measure for calculating an accessibility index.

This new product, classifying Italian municipality w.r.t. access to major transport facilities, allows users to measure infrastructure accessibility of municipalities by car, using the administrative territory as of January 1, 2021 (7,903 municipalities, with Rome divided into 15 sub-administrative areas).

The following infrastructures are considered:

• 258 railway stations (source: RFI, 2022) with active passenger and long-distance train services;
• 2842 access points to motorway network (source: TomTom, 2022);
• 35 commercial airports (source: ENAC, 2022);
• 54 statistical ports with passenger traffic (source: ISTAT, 2022).

In this study, the following accessibility indicators are included, from the simplest to the most complex:

• Cost to Closest: This is a simple indicator that can be interpreted immediately and that serves as a basis for the subsequent indicators. It measures the cost of travel from a given point of departure to at least one of the selected destinations. In this context, such cost is expressed in terms of minimum travel time by car.
• Accessibility/proximity cluster: A municipality (or an area in general) may be more or less accessible, either because of difficulty in reaching infrastructures or because of absence of nearby infrastructures. These two situations may require different policy interventions: on the one hand, investment in road network improvement to reach existing infrastructures, and, on the other hand, investment in construction of new infrastructures.
• Accessibility Index from Gravity Model: This indicator introduces a differentiating element by considering services offered by each infrastructure. This model defines accessibility as potential for opportunities. It allows to take into account choice behavioural aspect into the analysis. In other words, it assumes that, given the same travel distance, people choose to travel to infrastructures offering the most services.