Marginal Cost Controversies in Swedish Transport Infrastructure Policy

It is important that resources spent in transport infrastructure systems come to the best possible use. During the last four decades it has generally been argued that good resource utilization most likely comes about in cases where welfare economic principles are pursued. This holds both for the planning of transport infrastructure measures based on cost benefit analysis and for the use of the existing systems based on prices reflecting the short term social marginal costs of the transportation actually carried out. This article argues that, seen in a longer time perspective, there has however been a controversy regarding which financing principles that should be seen as most accurate. And this controversy has been persistent in Sweden since the 1930s. An institutional perspective where the direct relation between the users and the organizations that manage the infrastructure system, and with an interest for dynamism, learning and organizational aspects, has been in conflict with the welfare economic perspective. According to the institutional perspective the users should pay the full cost and subsidies by the public sector are questioned. An outcome of the present turn in the transport infrastructure discussion, with more interest for alternative financing and demand for heavy new investments, might be a revival of full cost principles in financing rather than marginal cost models. Once again the financing and pricing principles and their relation to efficiency might become a centerpiece of the debate.

交通基础设施系统的投入资源理应得到最优配置，这一点至关重要。近四十年来，学界普遍认为，唯有遵循福利经济学原则，方能实现资源的高效利用。这一结论既适用于基于成本效益分析（cost benefit analysis）的交通基础设施建设规划，也适用于基于反映实际开展的运输活动的短期社会边际成本（short term social marginal costs）定价的既有系统运营。然而，从更长的时间维度来看，学界围绕“何种融资原则最为合理”一直存在争议，且这场争议自20世纪30年代起便在瑞典持续发酵。制度视角与福利经济学视角向来存在分歧：前者聚焦基础设施使用者与运营机构间的直接关联，强调动态性、学习性与组织层面的因素；依据制度视角，使用者应当承担全额成本，而公共部门的补贴则备受质疑。当前交通基础设施讨论出现转向：各方对多元化融资模式愈发关注，同时对大规模新增投资的需求高涨，这一转向可能催生融资领域全额成本原则（full cost principles）的复兴，而非边际成本模型（marginal cost models）的延续。融资与定价原则及其与效率的关联，或将再次成为学界辩论的核心议题。