The main purpose of the article is to develop an optimisation pattern for the process of a preventive evacuation of people from flood-risk areas (at the first sign of a flood), aimed at mitigating the negative effects of the flood performed through the application of modern computer tools. It has been assumed that the use of both GIS tools and apps for vehicle traffic modelling (the research includes the use of a method developed by the authors) in emergency procedures implemented in response to a flood may increase the efficiency of the anti-flood campaign (here: the evacuation of residents from flooded areas), and thus, it may also minimise the negative effects of the flooding itself. The article distinguishes 14 stages of research, which were chiefly completed by means of the following methods: distance-based accessibility, cumulative accessibility, the Enhanced Two-Step Floating Catchment Area Method (E2SFCA) and the Two-Step Floating Catchment Area Method (2SFCA), the vehicle routing method, algorithms by Dinitz, Edmonds-Karp, and Ford-Fulkerson, and a comparative method applied to draw a comparison between the actual state of affairs and the optimum condition determined by the aforementioned methods.

The main purpose of this article was to develop a method of researching accessibility in the event of a flood through the application of measurement based on mobility. In the course of the research, it has been proven that changes in mobility (and the related travel speed) are too significant to be ignored when studying accessibility in unusual circumstances. The vast majority of existing accessibility studies rely primarily on speed models, which – in the event of a flood – do not indicate the external effects of the natural disaster. On the basis of the conducted research it has been stated that the occurrence of a flood has a significant impact on changes in the spatial distribution of traffic and its related speeds. Such changes vary depending on the particular means of transport. With the most commonly applied methods of measuring accessibility, which are customarily based on speed models, the changes we observed would not be recorded. The application of mobility-based research in the analyses of accessibility – especially in the event of a flood – indicates the disaster’s influence on the capacity of the road network, and thus, it allows for more effective flood-risk management. Furthermore, this article also demonstrates the possibility of applying source materials available in most member states of the EU, i.e., flood-risk maps and digital terrain models (NMPT), for the purposes of analysing and identifying road section closures within the transport network after the occurrence of a flood.

The article contains the evaluation of indirect impact, and more precisely, effects related to traffic disruptions and the resultant changes in transport accessibility following the occurrence of a flood. The applied purpose of the analysis is to demonstrate the differentiation in spatial traffic distribution and changes regarding (time and potential) accessibility in three flooding scenarios for the Warta Water Region (the scenario 10% and 1% probability of a flood occurrence, and for the total destruction of stopbanks) in Greater Poland. The research showed that the occurrence of disruptions from untypical flooding impacts both the change in spatial distribution of traffic load within the road network and the speed at which its users can travel therein. This indicates the need to simulate various flooding scenarios in order to be better prepared for the occurrence of such a natural disaster.

Wewnętrzna samochodowa dostępność transportowa Łodzi w świetle pomiarów z Inteligentnych Systemów Transportowych