World Bank is applying to transportinitiatives a new and distinctive method of greenhouse gas(GHG) analysis as part of its comprehensive GHG accountingpolicy. In transport, choices by travelers determine usage,and a fundamental trend in much of the world is stronglyboosting GHG emissions: the massive rise in motorization ashousehold incomes and technical advances make it affordable.This tendency will push transport fuel emissions much higherunless projects sharply expand the opportunities andincentives for users to adopt low-emission modes. The WorldBank’s GHG analysis for transport shows whether a giventransport project can help lower the trajectory of thesector’s GHG emissions. A central feature is an estimate ofthe wider social costs of emissions under various modes, forexample, air pollution and accidents, as well as climatechange. Including them greatly increases the demonstratedbenefit of emissions reducing projects and thus will alsohelp accelerate the move to a sustainable transport sector.