Abstract
For the purpose of providing public goods (e.g., air quality, congestion management, and greenhouse gas mitigation), the transportation sector employs and should employ imperfect policy instruments, such as fuel taxes, feebates, emission standards, and tolls. Then, policymakers need knowledge of the sector and how it can be more environment-friendly. With examples from cars to maritime shipping, common themes in environmental improvements beyond technology improvements exploitation of scale economy, capacity utilization, and slower speeds have been highlighted. Imperfect instruments ask for awareness of a broader set of environmental responses. Fuel taxes will, to some extent, succeed in eliciting responses, such as scale economy, capacity utilization, slowdown, and mode change from air to surface, from road to rail, and from rail to sea. Standards often work narrowly through technology and new acquisitions, such as individual vehicles or vessels.