This document summarizes a study on the incidence and regressivity of fuel taxes in Central America. It outlines the policy context of addressing air pollution and greenhouse gases through fuel taxes. It describes the study's goals of using household survey data from Costa Rica to calculate average fuel expenditures and the price elasticity of demand. The results found that a 10% fuel tax would increase expenditures the most for higher-income households in the short run. Issues with other country data are noted.