RISK-BASED TRANSPORTATION-PLANNING PRACTICE - OVERALL METHODOLOGY ANDA CASE EXAMPLE

We are faced with various types of risks in our everyday lives and con tinue to be exposed to new risk sources. Decision makers are continual ly faced with deciding whether a new risk source should be allowed in a particular community. Before making such decisions, it is desirable to know what the existing risks are, and what additional risks a new f acility would bring. Then, if there are established guidelines for ris k acceptability, planning decisions can be made so that some segments of the society are not exposed to unduly high risks, especially risks over which they may have very little control. Quantitative risk assess ment (QRA) techniques are playing an increasing role in analyzing safe ty of industrial systems, such as transportation networks or fixed ind ustrial facilities. The present paper discusses the commonly used QRA techniques and provides a review of measures of risk acceptability. Pa rticular emphasis is given to the fundamentals of quantifying risks ne ar transportation corridors, which are linear risk sources as opposed to the more familiar fixed point sources of risk. The methods are demo nstrated through a real life example: assessment of risks due to rail transportation of dangerous goods in the Greater Toronto Area. Where a ppropriate, comparisons are made with recent transportation routing li terature. Recommendations are provided for further research.