The Kyoto Protocol Clean Development Mechanism (CDM) is currently the only United Nations Framework Convention on Climate Change (UNFCCC) market mechanism that includes transport projects in developing countries. This mechanism has the dual objective of promoting sustainable development and contributing to green-house-gas emission reductions. However, transportation is currently a niche sector within the CDM due to the small number of transport projects registered under it. This is despite transportation being one of the sectors with the fastest growth-rate of greenhouse-gas emissions in the developing world. This paper examines the limitations of CDM-registered transport projects to achieve long-term sustainable development outcomes through the CDM. The experience of project ‘TransMilenio Phase II – IV’ in Bogotá (Colombia) serves to argue that CDM registration requirements of Additionality and Fixed-Term Crediting may be detrimental to achieving these outcomes through the CDM. Thus an opportunity exists to increase the significance of the transport sector within the international climate change regime through a dedicated ‘Sustainable Development Package for Transport’ in future agreements.