Evaluating government road tolling initiatives ex-post: An econometric assessment with evidence from Norway
本文利用挪威1984至2020年间约90%的收费公路项目数据，通过计量方法评估政府收费预测的系统性偏差及收费时长的影响因素，发现收费通常比计划提前1.45年结束，但预测存在系统性偏差。
Toll road initiatives play a pivotal role in financing infrastructure projects, particularly when traditional government funding sources are constrained. These initiatives typically involve imposing tolls for a predefined period, after which tolls are removed to reduce the long-term financial burden on road users. Despite their widespread application, the transportation literature offers limited systematic evidence on how governments meet their stated tolling objectives, the potential biases in their forecasts, and the determinants of deviations from planned outcomes. This paper addresses these gaps through an ex-post evaluation of Norwegian toll projects implemented and completed between 1984 and 2020. Covering approximately 90 % of all relevant cases during this period, the study uses robust econometric techniques to assess the presence of systematic biases in government forecasts and identify key factors influencing the duration of tolling. The results reveal several important findings. First, the government’s primary objective—removal of tolls within the planned time frame—is generally achieved, with tolls being removed, on average, 1.45 years earlier than estimated. Second, traffic volumes tend to exceed forecasts, while cost estimates are typically optimistic, resulting in modest overruns. Third, although mean percentage errors indicate moderate under- and overestimations—well within expected margins and significantly smaller than the forecast deviations commonly reported internationally—statistical tests confirm that the government’s forecasts are systematically biased. This suggests that the deviations are not due to random variation alone but reflect consistent patterns in estimation. Finally, variations in toll durations are significantly influenced by financing conditions, particularly interest rates, as well as project characteristics such as road type, centrality, and cost structure. These insights demonstrate that Norway’s tolling system has largely delivered on its promises and highlight the importance of refining forecasting methodologies for future policy planning. This study underscores the value of ex-post evaluations in understanding infrastructure performance and calls for more empirical research on the fulfillment of public sector commitments in transport financing.