Vehicles damage roads and, thus, increase road repair costs and create a road damage externality by raising the operating costs of subsequent vehicles. The main result is that if periodic road maintenance is condition responsive and if all road damage is attributable to traffic, then, in steady state with zero traffic growth, the average road damage externality is zero a nd the appropriate road damage charge is the average maintenance cost. Where weather accounts for some road damage, the road damage externality is no longer identically zero, but is quantitatively negligible. Road charges now recover a fraction of road costs. Copyright 1988 by The Econometric Society.

Most studies of commodity price stabilization assume that all agents behave competitively. However, many commodities suitable for stockpiling are produced by countries with a significant share of the world market, and commodity agreements themselves often result in cartelization of the market. The paper explores the consequences of market power for the choice of storage rule and the degree of price stabilization. It finds that with linear demand, dominant producers choose more stable prices than under perfect competition and price stability increases with their market share. With constant elastic demand the competitive degree of price stabilization is achieved.