Comparative Risk Assessment of Transportation of Hazardous Materials in Urban Areas

Abstract

The transportation of hazardous materials (HAZMAT) through urban areas is one of the most challenging risk-related issues faced by modern society. Society cannot function without this activity, yet the concentration of people and property in urban areas makes the potential for damage due to a HAZMAT release very high. Clearly, a methodology is required to systematically identify and quantify risk in this situation, help develop mitigation measures, and evaluate the effectiveness of such measures.

This paper describes a methodology to perform a microlevel risk analysis at street level in an urban area, thereby achieving the above objectives. The methodology requires studying each transportation movement through the urban areas in terms of material transported, quantity transported, vehicle characteristics, characteristics of the route (land usage, length, speed, type of road), and potential release scenarios. When the transportation pattern of a particular commodity is too complex to analyze, typical movements can be used as substitutes.

Then, using historic accident frequency and release consequence databases, a comparative risk index is obtained for each movement. (A spreadsheet program is used for calculations.) The effects of mitigation measures, such as additional regulations requiring changes in route and vehicle characteristics, can then be studied by comparing the risk index numbers for various possibilities. The paper illustrates the methodology, using an example.