Reducing Carbon Emissions from Transport Projects

Evaluation Document | 1 July 2010
This evaluation knowledge brief provides new tools to measure how different transport projects funded by ADB affect carbon emissions and offers suggestions to reduce ADB's transportation sector carbon footprint.

As the key development partner in Asia, ADB needs to explore opportunities to reduce carbon emissions and attract funds for low carbon initiatives. Funding for land transport projects comprises 96.5% of ADB’s total transport sector assistance.

ADB's Strategy 2020 envisages helping developing countries move their economies to low-carbon growth paths to reduce the carbon footprint of Asia's cities. This evaluation knowledge brief provides tools and knowledge that can inform such efforts. The study is based on ADB’s transport assistance approved between 2000 and 2009.

The study identifies economic analysis tools that ADB could use to better monitor and evaluate its carbon footprint in the transport sector. These can be used in conjunction with other analysis tools that take into account costs and benefits of specific types of transport services and their development impacts. The study says ADB should consider increasing awareness of carbon emissions in the design, appraisal, and review of projects. This could entail establishing baselines to measure progress in reducing the intensity of future carbon emissions.

The study recommends a modal shift in ADB transport investments in which the prime factors are currently the provision of access and mobility. It says ADB could also consider lowering the intensity of its carbon footprint by expanding its investments to new modes, such as non-motorized transport and bus rapid transit systems.

It also suggests that ADB consider adopting systematic indicators to monitor the intensity of carbon emissions from its transport investments in line with the emphasis given in Strategy 2020 to climate change issues.

Tools of the Evaluation

This study has developed quantitative tools for assessing and analyzing carbon emissions and air pollutant emissions of transport projects funded by ADB. The section on Methodology for Transport Emissions Evaluation Model for Projects in the complete report needs to be read in conjunction with the evaluation models.

Model 1: Rural Roads and Highways Project

This model can be used for roads located in rural areas, which are typically two-lane single carriageways designed to expand existing capacity in the non-urban context, costing $0.5 million–$1 million per kilometer (km). It can also be used for rehabilitated roads that are either one-lane or two-lane single carriageways projects designed to improve pavement surface, costing less than $0.5 million per km.

Model 2: Urban Roads Project

This model can be used for roads located in urban areas, which will typically witness high growth in traffic after completion, referred to as induced traffic in this study.

Model 3: Nonmotorized Transport (Bikeways) Project

This model is suitable for bikeways or similar urban nonmotorized transport systems that provide mobility through improved infrastructure.

Model 4: Expressways Project

This model can be used for expressways projects that are four-lane intercity dual carriageways costing more than $1 million per km. It incorporates induced traffic, as mentioned in this study.

Model 5: Urban Transport—Metro Rail Transit System

This model has been designed for metro rail transit projects that are urban rail-based systems with two tracks.

Model 6: Urban Transport—Bus Rapid Transit System

This model can be used for bus rapid transit systems involving a combination of public transport system and traffic management.

Model 7: Railways Project

This model can be used for railway projects that are intercity freight and passenger transport systems.


  • Executive Summary
  • Introduction
  • Evaluation Methodology
  • Key Findings of the Carbon Footprint Analysis
  • Implications for ADB
  • Recommendations