This digital document is a journal article from Economics Letters, published by Elsevier in . The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.Description: An optimal first-best road charge should not only be differentiated with respect to factors that affect the direct external environmental and time costs from the road-user himself. Indirect effects, such as the fact that others' cars will be more polluting when congestion increases, should also be taken into account.