The Common Market for Eastern and Southern Africa (COMESA), the East African Community (EAC) and the Southern African Development Community (SADC) Tripartite Regional Economic Communities (RECs) are deepening regional economic integration through working together on market integration, infrastructure development and industrial development. In the area of infrastructure, the efficiency and reliability of transport corridors are improved through addressing infrastructure constraints and operational inefficiencies, improvements in policies and procedures, corridor institutional development and the promotion of coordinated approaches to planning, programming and financing.
In 2009, the Tripartite RECs launched a pilot transport corridor programme, the North-South Corridor Aid-for-Trade Programme, spanning 8 countries, 3 RECs and a total of 10,647 km of road (8,746.3 km excluding South Africa) . This road network is the busiest transport network in the Tripartite region in terms of both traffic and freight volumes. Approximately 95% of all imports and exports transported along the NSC Aid-for-Trade network are transported by road, and only 5% by rail.
Since 2009 the PPIU and partners have been doing well in progressing projects through the project cycle. The average preparation  time of approximately 14-22 months for the current PPIU portfolio of in-country roads compares well with the World Bank average for similar projects, especially since the PPIU and TMSA have had to develop and implement a new set of procedures (such as regional procurement procedures) before a start on project preparation activities could be made
Between March 2010 (year 2009/10) - February 2014 (year 2013/14):
- The total km of road being actively prepared increased from 25 in 2010 to 1,090 km (along with the Sir Otto Beit Bridge Project) in 2013. By February 2014, preparation on 604 km of these roads had been completed. Completion of the design aspects of the preparation phase of the remaining 486 km of road is now on hold due to funding constraints
- 833.9 km of road progressed to the implementation phase. 808.9 km is funded by partners while the TTA is funding the remaining 25 km in addition to the Kafue Weighbridge Project.
- The African Development Bank committed to fund the preparation of 700 km of road (10 road links) through the PPIU. Following DFID decision to close the PPIU at the end of March 2014, the future of these projects is unclear
The total financing required to prepare all priority North-South Corridor projects currently in the PPIU project pipeline (thirty-three projects of 3,212.3 km) amounts to approximately US$ 20.3 million (see table 6 below). A total of US$ 14.5 million has been committed by development partners,including DFID, EDF and the AfDB. Since DFID’s withdrawal of preparation funding, the shortfall has increased from US$0.69m to US$5.74m for preparation of all projects (assuming that the balance of the EDF Grant for Serenje-Nakonde (EURO 5 million) which is not used for Serenje-Nakonde becomes available for other NSC projects, and if the AfDB-NEPAD-IPPF Grant of US$ 4.5 million materialises as committed). The total financing required to implement all 49 projects along the North-South Corridor (including PPIU and Partner Projects) amounts to approximately US$ 3,530 million (3.5 billion) (See table 7 below). An estimated US$ 759 million has been committed by development partners and countries (including the TTA, the World Bank, DANIDA and the Governments of Botswana, Zambia and Tanzania). The amount withdrawn from TTA by DFID in November 2013 (previously available for NSC Projects) is US$ 73 million (GBP 44 million). Therefore a remaining shortfall of US$ 2,771 million (2.8 billion) is therefore required to implement all priority NSC road projects - a total of 4,046 km.
 The NSC Aid-for-Trade road network includes the road corridors defined by SADC as the North-South Corridor (NSC), the Dar es Salaam Corridor and segments of the Trans-Kalahari and Nacala Corridors.
 “Project Preparation” as used here includes award of design contract, preparation of detailed designs and bidding documents, preparation of Environmental Impact Assessment and Social Impact Assessment studies, as well as preparation of final stage PIM document. Additional outstanding feasibility and impact analysis studies will require additional time and funds to be completed.