Risk assessment - an introduction

This paper introduces the concept of risk and identifies the statutory requirements for performing risk assessments. It discusses the differences between qualitative and quantitative risk assessments and their advantages and disadvantages. It looks at why we must undertake risk assessment and how this is encompassed within the railway safety case. For the purposes of this paper we shall consider safety assessments where risk is defined in terms of the chance of an accident occurring and the severity of the accident. We can accept more accidents if the consequences are only minor injuries, but can accept only very few accidents where several fatalities may result