Geographic Accessibility Analysis - Methods and Application

Abstract: Geographic accessibility to services is important. Having a grocery store and a school nearby are important living conditions and having a rescue station close by could be a life-saver. Costs for transportation are high and are predicted to increase, new environmental demands are being imposed on transportation and rationalizations are centralizing public and commercial services. These facts make monitoring and planning accessibility increasingly important. Efficient computer systems for accessibility monitoring and planning could be used to improve accessibility to services. The aim of this study is to establish such efficient methods for geographic accessibility analysis and test them in computer applications. This was performed by studying effective ways of structuring data, algorithms for network searches and implementing these theories in test benches and application prototypes. Geographic accessibility to services is essential, especially when long distances must be covered, as in rural areas. The Swedish National Rural Development Agency (SNRDA) analyses accessibility to services from a national perspective, with the focus on rural areas. This is done using a computer model that is implemented in a Geographical Information System (GIS). This study investigates the foundations of the representation of road networks, connecting points to a network and accessibility studies through network searches. The results of this dissertation are meant to be used to develop the next generation of the system. Three papers are presented in this dissertation. The first deals with an evaluation of an existing accessibility analysis system at the Swedish National Rural Development Agency. The focus of the study was to identify performance bottlenecks in the SNRDA’s accessibility system and the problem areas that were found would then guide further research. One of the bottlenecks found in the study was the process of connecting points to large networks. This is investigated in the second paper and suggestions for solutions of the problem are presented. The third study is an applied study for planning accessibility to rescue services. This study concentrates on an application prototype called the Rescue Unit Planner (RUP) used for planning accessibility for non-stationary rescue units. The conclusions of this dissertation are that it is possible to build more efficient systems to perform accessibility analysis. The studies in this dissertation will support the further development of the SNRDA accessibility analysis system, which also was the overall goal.