A time-based model and GIS framework for assessing hazardous materials transportation risk in urban areas

Every day, trucks carrying hazardous materials (hazmat) in a large and densely populated city expose public health risks to the residents of the city as well as risks to the economic assets in the area. In this paper, we introduce a new risk model that considers population exposure along a route and the duration of such exposure, the latter being variable due to the congested nature of road transportation in urban areas. We have developed a spatial decision support system (SDSS) for quantitative risk analysis and the calculation of minimum-risk paths as well as their visualization on digital maps. We illustrate the usage of our proposed model and SDSS via a case study using the real road network of Istanbul, Turkey, a large metropolitan area with more than 15 million residents. We analyze Istanbul's hazmat transportation risk profile using risk analysis techniques via our interactive Geographical Information Systems (GIS)-based decision support system. We then produce a risk map of the city and run several routing scenarios between selected hazmat shipment origins and destinations. Results suggest that the hazmat routes under the new model may not always match with how hazmat is usually transported, with an economic decision-making perspective, in an urban area. Our proposed approach provides decision makers with new insights into urban hazmat transportation and is likely to reduce the consequences of incidents with large impact on public health.