GIS-BASED RISK ASSESSMENT IN THE TRANSPORTATION OF HAZARDOUS PETROLEUM PRODUCTS BY ROAD ACROSS A DENSELY POPULATED URBAN CENTRE IN NIGERIA

Abstract

Road shipment of hazardous materials (hazmat) is generally associated with significant level of risk. Hazmat shipment needs to be transported under a safe condition without posing significant risk to human and environmental health. The paper focuses on transportation of hazardous petroleum products such as petrol across the city of Ogbomoso, Oyo State, Nigeria. While the traditional routing is based on minimizing distance and travel cost. This paper presents a risk based Geographical Information System (GIS) model for identifying the least-risky routes for the transportation of hazmat. The risk considered in the model is basically population exposure since the safety of lives and properties is paramount. Global Positioning System (GPS) device was used to track the freight route to identify potential risk points in the study area. ArcGIS 10.5 was used to plot the tracked point data, performed buffer operation to determine the different risk level at 800meters (m) distance and query distance measurement. The produced risk map from buffering operation was overlay on other land used type in the study are to determine the level of population exposure. Kernel density was used to calculate a magnitude per-unit area from point or polyline features using a kernel function to fit a smoothly tapered surface to each point or polyline. Valued attributes were selected and assessed. Using a buffer area of 800metres, the findings revealed that substantial number people living within the exposure area are at risk of hazardous material disaster in addition to properties of high economic value. The study developed an alternative routes to reduce the population exposure risk should be used in the transportation of hazardous materials across the city. The result of this study provides guide city planners, stake holder in the hydrocarbon products transportation industry and policy maker on effective freight method of their products across the metropolis while preserving the risk level within the Ogbomoso city. The result of this study can be applied in a city of similar economic, population and urbanization pattern for sustainable hydrocarbon product movement to the retail points.