Valuing in actual travel time environmental encroachment caused by transport infrastructure

Most cost-benefit analyses used in transport infrastructure planning do not include the possibly significant cost of encroachment on valuable environments. Standardized values are used for other effects, but encroachment costs are difficult to transfer because of heterogeneity, uniqueness, and the importance of substitutes. A problem with stated preference methods is that the choice of hypothetical payment vehicle can affect the willingness to pay. An approach using actual travel time savings as payment vehicle when valuing environmental encroachment caused by transport infrastructure is presented, including two applications. Since different people have different travel patterns the travel time saving resulting from, for example, a new road in the area will naturally vary. By asking a large number of people whether they want the encroaching road or not and correlate their answers to their actual travel time savings, it is possible to estimate the average willingness to substitute travel time for the encroachment caused by a specific planned road. This encroachment cost can be included in the CBA for the transport infrastructure project.