The application of contingent valuation surveys to obtain willingness to pay data in road safety research: methodological review and recommendations
Willingness to pay is increasingly utilized in cost-benefit analysis research in road safety. In other fields of research such as environmental and health policy evaluations, contingent valuation (CV) surveys have been developed and widely used as a method to elicit people’s willingness to pay for the products being evaluated. Many authors have provided methodological critiques on CV surveys, which have been shown to be subject to various forms of biased responding such as hypothetical bias, starting-point bias, and strategic response bias. Various ways to control for these biased responses exist including the design of the survey and statistical analyses. Furthermore, different results have been found depending on the elicitation methods used (e.g. open-ended question versus referendum format; ex-ante valuation versus ex-post valuation), and the ways in which the context of the product provision is described and the product framed (e.g. private product versus public product) for the same product being valued. These methodological critiques are relevant to the use of CV method in road safety research that intends to elicit willingness to pay for road safety products. Furthermore, employing evidence-based survey designs and question forms are critical to obtain the best possible willingness to pay data in road safety research. The current paper presents the methodological limitations of CV surveys identified in previous research and offers best practice recommendations for CV survey designs in road safety based on the CV methodological literature.