How can cyclist injuries be included in health impact economic assessments?

Abstract

This paper discusses how injuries sustained while cycling can be included as a component of health impact economic assessment of increased cycling. To include injuries as a component of a health impact assessment, their expected frequency of occurrence and impacts on health must well known. In this respect, incomplete reporting of cyclist injuries in official accident statistics is an obstacle for good health impact assessment. It is convenient to represent injuries in terms of an expected loss of health per cyclist or kilometre cycled, which can be converted to monetary terms to make it comparable with the health benefits. It is suggested that stating health loss in terms of DALYs (Disability Adjusted Life Years) is suitable for this purpose. Examples are given of how to estimate the health loss associated with bicycle injuries. It is more difficult to model the probability of injury. Two approaches are compared. One approach relies on the relationship between distance cycled per year and risk of injury. The other approach is based on the concept of safety-in-numbers. The number of injuries is modelled as a function of the number of cyclists and motor vehicles. Results are found to be greatly influenced by the assumptions made about whether increased cycling occurs as a result of modal shift from motor vehicles or not.