The travel cost method aims at estimating the value people place on a particular environmental feature by analysing how much they are paying to visit it, in terms of travel and admission costs (if any). This method is often used for valuing recreational amenities like parks, forests, and beaches. By analysing how many people visit the site at different price points, we can estimate the demand curve for the amenity and derive a value for it. 

The travel cost method is the most established revealed preference approach to estimate the recreational value of natural sites. This approach estimates the “consumer surplus” associated with a visit, which represents the difference between the maximum amount a visitor is willing to pay for visiting the site and the actual cost incurred in traveling to the site. In other words, it is the net increase in well-being that an individual experience by visiting the site. This well-being can, as usual, be expressed in monetary terms. The travel cost method can be used to estimate the value of the site as a whole, or some specific characteristics of sites, such as the amount of fish biomass or coral cover. 

There are two main travel cost approaches: the single-site travel cost and the multi-site travel cost. The single-site travel cost method is simpler to implement, and focuses on estimating the value of a specific site, for example, a beach, but can be also used to assess the value of a larger area (such as a region with several beaches). The multi-site travel cost method is more complex, allows estimating the value of multiple, heterogeneous sites within a region, and the simulation of many different and spatially explicit policy scenarios with changes in both site accessibility and environmental quality (e.g., Fezzi et al, 2023).