Transportation system connectivity is drawing increased focus within local, state and federal planning circles assmart growth, active living, growth management, sustainability and climate change policies and programs stresssmarter decision-making. This study examines seven transportation system connectivity metrics to determine whichis best for measuring the benefits of micro-scale connectivity improvements.Study findings show that the direct measurement of connectivity by means of a route directness index(RDI) can be effectively and consistently applied across varying contexts, including rail transit station areas, firestation service areas, and non-motorized transportation system improvements. The analysis conducted for the sevenstudy locations in a variety of multi-modal project contexts indicates that utilization of RDI provides for greaterability to analyze subtle changes in the transportation system and weigh the benefits of such improvements at theparcel level within a study area. RDI was also found to be a more robust measure of connectivity for analyzing andquantifying the benefits of a variety of sustainable community issues, including quality of neighborhood networks,improving transit station accessibility, and emergency services response / fire station access—sustainability-relatedcomponents that should be considered in transportation project design.Study examples and findings illustrate how connectivity metrics differ in their abilities to measure thebenefits among specific system improvements. While helpful in raising awareness and guiding better landuse/transportation system development, study findings suggest that current policies and programs employing proxymeasures of connectivity (e.g. link-node ratio or intersection density) have limited utility as performance-basedanalytical tools. Point-to-point GIS metrics such as RDI can recognize subtle changes to system connectivity(necessary for evaluating improvement alternatives), whereas proxy measures are insensitive to these changes‥
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