CROSSING DUPUIT'S BRIDGE AGAIN: A TRIGGER POLICY FOR EFFICIENT INVESTMENT IN INFRASTRUCTURE

This paper borrows Dupuit's parable of a bridge so as to reexamine the problem of selecting and financing public investment projects in a dynamic and strategic setting. A regulator imposes a price ceiling, and a firm makes a sunk investment each period. Three simple examples reveal the connection between the non-cooperative equilibrium of this relationship and the second-best optimum. One cannot implement this "planning solution" generally since the firm and the regulator each behaves opportunistically toward the other's irreversible actions. The facility never will be built if investment in it is infinitely lumpy and if the facility is perfectly durable. Departing from this extreme case, however, one can restore proper incentives by adopting "trigger policies." The regulator responds to a deviation from a candidate path by cutting price down to operating cost, and the firm halts all investment. If capital does not depreciate too slowly and the future is not discounted too much, then one can approximate the planning solution by an equilibrium. The success of trigger policies suggests that reformers should relax many regulatory rules and procedures to support efficient investment in infrastructure. Copyright 1991 Western Economic Association International.