Including the Environmental Impacts of Roads in Project Evaluation and Decision-Making

The environmental impacts of roads are of increasing community concern. There is growing recognition that the environmental impacts of road projects should be better included in project decision-making and project evaluation. As well as measuring environmental impacts, there is a need to better incorporate them into decision-making. Continued improvements in the technical methods of measuring and quantifying environmental impacts will be invaluable. However measurement is only part of the issue: impacts must also be compared with other project costs and benefits. Assessment of impacts is discussed including non-monetary assessment of impacts and monetary valuation. It is argued that monetary valuation of environmental impacts would improve decision-making, as it would allow for more impacts to be quantified in a common unit, improve consistency and make trade-offs more explicit. There are a number of techniques available for monetary valuation. Methods which rely on hypothetical markets (contingent valuation and stated preference methods) offer great promise and have yet to be fully utilised in this context. As an indication of the costs of environmental impacts, som