Title

Safety models incorporating graph theory based transit indicators

Document Type

Journal Article

Publication Date

2012

Subject Area

planning - network design, planning - safety/accidents, mode - bus

Keywords

Collision prediction models, Safety planning models, Safety performance functions, Network techniques, Transit indicators, Connectivity, Coverage, Directness, Complexity of transit networks

Abstract

There is a considerable need for tools to enable the evaluation of the safety of transit networks at the planning stage. One interesting approach for the planning of public transportation systems is the study of networks. Network techniques involve the analysis of systems by viewing them as a graph composed of a set of vertices (nodes) and edges (links). Once the transport system is visualized as a graph, various network properties can be evaluated based on the relationships between the network elements. Several indicators can be calculated including connectivity, coverage, directness and complexity, among others. The main objective of this study is to investigate the relationship between network-based transit indicators and safety. The study develops macro-level collision prediction models that explicitly incorporate transit physical and operational elements and transit network indicators as explanatory variables. Several macro-level (zonal) collision prediction models were developed using a generalized linear regression technique, assuming a negative binomial error structure. The models were grouped into four main themes: transit infrastructure, transit network topology, transit route design, and transit performance and operations. The safety models showed that collisions were significantly associated with transit network properties such as: connectivity, coverage, overlapping degree and the Local Index of Transit Availability. As well, the models showed a significant relationship between collisions and some transit physical and operational attributes such as the number of routes, frequency of routes, bus density, length of bus and 3+ priority lanes.

Rights

Permission to publish the abstract has been given by Elsevier, copyright remains with them.

Comments

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http://www.sciencedirect.com/science/journal/00014575