In the mid-1980s I did an undergraduate dissertation on road pricing. Alan’s work in this area (together with that of Gabriel Roth) from the early 1960s was brilliant. In 1984 it was still clearly the best exposition of the theory and the most comprehensive development of the theory available. Three contributions are worth mentioning.
The first was a paper in Econometrica: “The theory and measurements of private and social cost of highway congestion” (Econometrica, 29, 676 – 699). The second was The Smeed Report on which he worked (with Gabriel Roth, Michael Beesley and others), which was published in 1964. The third was The Economics of Road User Charges. Even today, there has been virtually nothing to add to that work of the 1960s, the first of which was published 47 years ago when Alan Walters was 35. The fact that Alan Walters’ work in that field (as in others) was so enduring yet comprehensible even to an undergraduate tells you something about his extraordinary insight and powers of exposition.