The foreseen population growth and related rising demand for transport will necessitate massive investment in new transport and infrastructure projects and the adequate maintenance of those already in place. Already today, transport investment needs are estimated to be between one and two trillion dollars per year. Of the current total annual investments worldwide, less than 40% is received by developing countries, where the needs, but also opportunities are the greatest. The Addis Ababa Action Agenda on Financing for Development, adopted in 2015, elaborates on the many approaches that will be needed to implement the 2030 Agenda, including traditional official development assistance, domestic resource mobilization, and a wide array of partnership models. The same diversity of approaches will be needed to finance sustainable transport in the 21st century.