This study suggests a model for enhancing accuracy in evaluating amenity by the contingent valuation method (CVM) when household`s willingness to pay (WTP) is dependent to its income and the distance between a respondent`s residence and the location of a target facility. Using a linear city model, this study demonstrates the influences of income and distance-decay effects on WTP. Simulations are performed to check the validity of the model as well as to predict consequences when income and distance-decay effects are not properly treated. Finally, the suggested model is applied to two real cases. The estimation results from a structural model show that the calculated total benefit varies largely when income and distance-decay effects exist and are ignored. Also, an ad hoc model generates significantly different estimates from the utility difference model this study adopted. The difference in estimates suggests that the total benefit has to be estimated by a structural model.