رویکرد نظریه بازی برای تخصیص ریسک مشارکت های عمومی ـ خصوصی در حمل و نقل

The process of risk allocation between public and private sectors in transport infrastructure agreements is analyzed as a bargaining process between these two agents. Such a process is modelled with a final offer arbitration game. The idea here is to analyze through a game framework the behaviour of the players when confronted with opposite objectives in the allocation of risks. The model shows that when guarantees have a higher value than financial loss we are confronted with strategic behaviour and potential moral hazard problems.

Concerted emphasis has been placed on the development of means by which the private and public sectors can forge partnerships to provide goods and services traditionally provided by the public sector. These partnerships between public and private (PPPs) find their roots in the policy notions of privatization/deregulation of the 1980s [1]. Among the various consequences springing from PPP agreements is the possibility for the public and private sectors to share and allocate risk borne with the investment. The sharing and allocation of risk in PPP agreements assumes greater importance when we examine infrastructure investments such as transport. Transport infrastructure investments are inherently capital-intensive and they often require large sunk investments whereby their recoup may span over a 30-year period. They are immobile; in fact, transport infrastructure investments are particularly cumbersome to transfer or reallocate elsewhere and, if reallocation were possible, it would imply prohibitive transfer costs [2]. However, in the past decade transport investment partnerships between the public and private sectors have become conventional practice in developed and developing countries. On the basis of the Maastricht criteria (1992), which requires a diversification of funding sources in the development and operation of transport infrastructures, the European Investment Bank (EIB) has supported the development of more than 100 PPP projects, covering multi-sectoral transport investments, in most EU countries for a total amount of signed loans over €15 billion [3]. A similar situation is apparent when we observe developing countries. From 1990 to 2001, nearly 2500 private infrastructure projects were implemented by the World Bank in developing countries, of which 662 were transport projects with an investment of $135 billion [4]. The intervention of the private sector in transport investment has shifted the responsibility, and thus fragmented the decision process, which in the past was taken on solely by the public sector. Risks associated with the investment therefore assume a crucial role. There are many experiences showing that transport investments are highly sensitive to risk allocation [3], [4] and [5]. For instance, governments can both enhance and depress the demand for a certain transport service by means of an ad hoc regulation. The experience of the Bangkok congestion charge is a case in point. In this case the Thai government, after having awarded a contract to the Bangkok Expressway Company Ltd. (BECL) for a 12-mile, six-lane private toll road, decided under the pressure of political lobbies and public discontent, to reduce the agreed toll. The BECL asked the government for a delay in the opening of the private road in order to settle the dispute. But the request was nevertheless denied, and the toll road opened under the adjusted toll regime, thus pushing the private company to bankruptcy. The objective of this paper is to examine the process of risk allocation between the public sector and the private sector in transport PPP agreements. The allocation of risks is examined as a bargaining process between the two agents confronted with the decision about risk allocation offers. Such a process is modelled with a final offer arbitration game. The idea here is to analyze through a game framework the behaviour of the players when confronted with opposing objectives in the allocation of risks. The two different behaviours of the agents will generate the most ‘fair’ offer, that is, the offer that reduces the probability of a bad outcome.

The allocation of risks between the public and private sectors when in partnership for transport investment is a cumbersome task because transport concessions are often subjected to opportunistic behaviour by the agents committed to the PPP contract. The objective of this paper has been to analyze the allocation of risks in PPP transport concessions. The allocation of risks has been examined here through the final offer arbitration game [22]. In the model, the agents compete to achieve the most reasonable offer in the settlement. In the standard game of final offer arbitration, the more risk-averse agent submits the more reasonable final offer and then has the higher probability of being selected by the arbitrator. The innovation of the model used here is that the probability for the arbitrator to choose one of the two agents’ offers is based on the level of guarantees that one agent is willing to give to the other. In particular, when the guarantees for risk exceed the financial loss related to the risk, the offer of the less risk-averse agent has the higher probability of being selected by the arbitrator. The implication of this result is that one of the two agents in the negotiation may act strategically in order to be selected by the arbitrator so that, given the level of guarantees, if the event related to the risk occurs, the agent who behaved strategically will realize a profit. We can conclude that in the case where guarantees have higher value than the financial loss related to the risk covered by the guarantees, a settlement rather than an arbitration agreement is especially advisable in order to reduce the effects of potential moral hazard problems.