November 1997 This model predicts that without cooperative infrastructure agreements between countries, there will be underinvestment in those forms of infrastructure in which the investments will have spillover effects to other countries. For a relatively small country, for example, there would tend to be more underinvestment in railroad and highway infrastructure to neighboring countries than there would be in airport and harbor infrastructure (carrying goods to the whole world). Bond examines whether trade liberalization should create a greater incentive for countries to invest in transportation infrastructure. He pays special attention to the case of preferential trade liberalization between neighboring countries, where investments in roads or railroads are specific to the partner country and will thus have spillover effects. The existence of spillovers will lead to gains from cooperative agreements about investment levels. Bond shows that in a small country the incentive to invest in infrastructure depends on the level of the tariff when demand is linear. If protection is in the form of a quota, on the other hand, trade liberalization will increase the optimal infrastructure investment. He shows that in a two-country model with spillovers between countries, the cooperative equilibrium may involve either more or less investment than the noncooperative equilibrium, depending on the pattern of trade between the two countries and the degree of substitutability between investments in the two countries. For a relatively small country, for example, there would be more underinvestment in railroad and highway infrastructure to neighboring countries than there would be in airport and harbor infrastructure. The first type of investment is specific to certain markets and is likely to affect the relative price of goods in those markets. The second type of investment, on the other hand, will send goods to world markets generally, where prices are likely to be relatively unaffected by the investments. Bond also examines the desirability of linking regional trade and infrastructure agreements. The prediction generated by his model is that in the absence of cooperative agreements between countries, there will be underinvestment in those forms of transportation in which the investments will have spillover effects to other countries. Bond identifies two forms of gains from infrastructure agreements: * Internalizing the terms-of-trade effects and thus avoiding the inefficient investment levels that arise in noncooperative choices of investment levels. * Internalizing the effects of the infrastructure investment in the tariff negotiation process, in cases where countries cannot commit to future tariff rates. This paper-a product of the Development Research Group-is part of a larger effort in the group to understand regionalism and development.