The RAND Corporation, a non-profit research institute based in the US and Europe, has released a report that provides an overview of the literature from both economists and transportation planners to underline what is known about the equity issues associated with congestion pricing. The goal of the report is to look at the evidence to determine whether congestion pricing is equitable. The authors have reviewed evidence from two types of source: evaluations of real-world congestion pricing implementation and models of proposed and hypothetical congestion pricing systems.
Literature on the equity implications of congestion pricing has two dimensions: economic and planning. The former is usually concerned with the distribution of costs and the benefits that accrue to society, while the latter generally focuses on the social justice aspects of congestion pricing, and the potential negative consequences for low-income and other disadvantaged individuals. The RAND report provides an overview of the principles underlying congestion pricing and how these have been incorporated into road pricing proposals.
According to the authors, it is difficult to draw firm conclusions about the equity implications of congestion pricing. They argue that there is no single answer to the question, “Is congestion pricing equitable?” The answer depends on how equity is measured and the groups defined, the specifics of the location and what congestion pricing is being compared to. Since it is almost impossible to reflect on all the facets of equity, it is important for policy makers considering congestion pricing to select the most relevant criteria for assessing equity in the perspective of local conditions and concerns.
The authors point out that many topics related to congestion pricing have received little or no study, and it would be helpful for the research community to begin devoting more attention to exploring them. These include the long-term land-use impacts of congestion pricing and the integration of congestion pricing into existing means of transportation finance (e.g., fuel tax).
Based on the analysis, two overall recommendations were made with a view to making congestion pricing proposals more equitable. Firstly, it was suggested that equity should be formally incorporated into the planning process, along with such considerations as cost, revenue generation and other implementation issues. In this regard, the authors proposed the development of a tool or guidebook for use by communities. Secondly, equity concerns should be monitored in the same way as environmental concerns, to ensure that project goals are met over time. In particular, the mechanisms developed to promote equitable outcomes should be assessed on a regular basis to ensure that they are meeting the goals set by the community concerned.
Any region addressing equity issues when implementing congestion pricing must determine how to define equity, how to measure it and how to promote it dynamically vis-à-vis other goals. According to the authors, despite extensive study and a number of empirical results, the question of whether congestion pricing is equitable must be answered in a manner specific to each region and each proposal.