Tool to quantify urban mobility externalities

From Communauté de la Fabrique des Mobilités

How to calculate GHG from urban mobility

💼 porté par CODATU, ADEME


In the frame of climate-related initiatives funded by donors internationally, one of the main issues is to measure GHG emissions to be able to account for the mitigation impact of the projects. It is the case for instance in many urban mobility-related programmes and projects, of which the MobiliseYourCity (MYC) initiative is an example, where GHG emissions are a major indicator developed according to the MRV (Measure-Report-Verify) approach. As detailed in MYC’s MRV methodology guide and ADEME reports on MRV-GHG in Morocco, there are several ways to calculate GHG from urban mobility. The ASIF methodology seems to be the most appropriate within the MYC context (where GHG emissions are one key element of the Sustainable Urban Mobility Plan), requiring Vehicles Kilometres Travelled (VKT) and average fuel economy (FE) of each vehicle type.

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Categories: Logiciel, Données, Connaissance, Communauté

Theme: Urbanisme et ville, Logiciel Libre, Collectivité, Africa


Challenge: Accompagner une collectivité à ouvrir un maximum de ressources et construire un kit d'aide à l'innovation, Faciliter le partage la gestion la maintenance la comptabilité des émissions polluantes et de GES des véhicules

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Community of interest: Communauté des acteurs en Afrique


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Level of development: Idée

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The ASIF methodology: the most common way to reach MRV for the transport sector[edit | edit source]

The ASIF approach is widely used by many stakeholders to quantify energy use and GHG emissions from the transport sector. The main components are traffic activity (VKT) and GHG emission factors (blue squares in the figure below).

The ASIF framework to calculate GHG emissions from the transport sector (MYC, 2017)

There are three main ways for getting the average fuel economy of the vehicle fleets in cities:

  • Performing a survey towards vehicle users to require their declared fuel economy; such declared values need quite a large sample for each vehicle type considered to get an accurate value;
  • Using an emissions inventory harmonized tool that derives average FE (Fuel Economy) from laboratory measurements on typical driving conditions for each vehicle type;
  • Producing data with specific app like GECO Air or devices.

Each methodological approach have their own advantages and drawbacks (Table 1).

CO2 emission factors from : Pros Cons
Fuel Economy Survey - More realistic value matching local context

- Getting technical information about vehicle fleet simultaneously

- Declared values

- Large sample needed for each vehicle type to get good accuracy

- Timescale to get results

- Surveys are expensive

Emission Inventory Tool - Real CO2 measurements

- Robust "MRV-compatible" methodology

- Allows for future projections for certain tools

- Incentive for all MYC countries/cities to collect the same information

- Pollutants also included

- Comparability across MYC countries/cities

- Requires the technical specifications of the vehicle fleet

- Cost of using the tool when it comes with proprietary rights

- Need of additional information about average speeds or level of congestion

Table 1 : Pros and cons of surveys and IT tool to get CO2 emission factors

This note focuses on the pros and cons of getting fuel economy information by using an emission inventory tool.

Why a harmonized tool ?[edit | edit source]

Using an emission inventory tool to convert VKT into CO2 brings several benefits compared with getting fuel economy values from a survey (see table 1).

There would be a need to be able to gauge and compare the efforts made by each country/city, check the transparency of each results put forward and assess the quality of the efforts made to mitigate GHG emissions.

For example, if a country states 100 MtCO2 saved and another 300 MtCO2 saved, a robust approach requires that the country saving 300 MtCO2 really saved 3 times more than the other country. A harmonized methodological approach would make sure this is possible. If each country develops its own inventory tool to quantify national GHG emissions from the urban transport sector, there is a high risk that the results obtained will not be comparable with the results from other tools. The essence of MRV procedure, making sure that results are harmonized and comparable, would then be missed.

By having a harmonized GHG quantification tool, one would make sure that methodologies and results would be more transparent and more easily comparable. It would also provide a strong incentive to collect the same information in all countries/cities engaged in clean urban transportation strategies and projects, which will be useful to characterize the urban transport sector and calculate GHG emissions.

Hence the recommendation to either adapting an existing tool or creating one adapted to developing countries context. Training would be provided by the tool editor and detailed user guide would be available

What tools are available?[edit | edit source]

As detailed in ADEME’s report on MRV-GHG strategies for Morocco, a short list of potential tools has been put forward that would fit for these purposes. Such a harmonized GHG tool should build on on the most adequate tools that are widely used across Europe to perform transport emission inventories:

Other institutes like IFEU (Institut für Energie- und Umweltforschung), could also be considered.

GIZ has already delivered a version of HBEFA to perform GHG emission inventories in Chinese cities. A slightly modified version of this tool would potentially be usable within other geographies.

As per COPERT, it is widely used by many stakeholders at the national and local levels, as it is freely available and all emission factors calculation equations are publically available.

Being widely used for emission inventories, such tools would qualify for MRV compatible strategies.

Tool needs[edit | edit source]

Key criteria for a relevant GHG quantification tool would include:

  • VKT input from different approaches (vehicle, inhabitant, infrastructure);
  • Emission factor database for vehicles from the early 1990s;
  • Provides default values for criteria used for emission factors determination (average speed, level of congestion, …);
  • Possibility to perform forward-looking projections until at least 2030.

Expected costs[edit | edit source]

Adapting an existing tool and/or developing a model/features not yet existing will require some financial resources.

If a tool with proprietary rights would be considered (such as HBEFA), getting a set of bulk licences would also involve extra costs.

Abbreviations[edit | edit source]

ADEME Agence de l’Environnement et de la Maîtrise de l’Énergie
ASIF Activity Structure Intensity Fuel
CO2 Carbon dioxyde
FE Fuel Economy
GHG Greenhouse gas
MRV Measurement, Reporting and Verification
MRV-GHG Measurement, Reporting and Verification for greenhouse gas
MYC MobiliseYourCity
NAMA Nationally Appropriate Mitigation Action
NUMP National Urban Mobility Planning
SUMP Sustainable Urban Mobility Plan (PDU)
VKT Vehicle kilometres travelled