Evaluation of accessibility of urban transportation networks

This thesis examines accessibility of urban networks to serve the transportation needs of a community. The term accessibility is dealt with qualitatively and quantitatively, giving it a form and structure readily adaptable for implementation by metropolitan planning organizations. Accessibility has been defined from the point of view of the network. This definition helps in interfacing the network with the traditional travel demand models. A methodology was enunciated to develop accessibility indices for urban areas and implemented by means of automated software. The trip generation stage in the traditional urban transportation planning process (UTPP) is used along with a geographic information system (GIS) based approach in order to develop a program that evaluates accessibility measures and presents them in a graphical manner. The indices are expected to aid transportation planners, managers of public agencies and decision makers to make the best use of available resources in making changes to the transportation system and also help compare the system accessibility both within the system and across various systems in a region. The methodology has been implemented and an alternatives analysis performed for the Las Vegas Metropolitan area. The implementation scheme utilizes the spatial analysis capabilities of GIS and interfaces with the UTPP. A suite of programs are developed in the GIS environment to automate the process to a simple menu driven system. Twenty-two indices have been defined and analyzed for the study area. These include five indices each for trip production and attraction parameters namely home-based work, home based school, home based shop, home based other and aggregate accessibility indices. Similarly, a combined model incorporating both the production and attraction models (consisting of six indices) and a demographic model (consisting of five indices) are also developed and analyzed