The travel cost method derive the economic value of recreational activities, based on the visitor's incurred costs for transportation and time used to conduct their activity in a specific recreational site, and the number of visits they make to the site. The travel cost method is only suitable for valuing the current value of accessing recreation services at a site, and needs to be supplemented with contingent behavioural data or expert assessments of changes in recreational use in order to value changes in recreational services. The methods rely on the collection of user data.