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Energy efficiency and specific CO2 emissions

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Justification for indicator selection

Transport accounts for almost one third of final energy consumption (see Eurostat energy statistics) and around a quarter of total CO2 emissions (see TERM 02 - Transport emissions of greenhouse gases). Energy efficiency improvements in transport can therefore result in considerable reduction in energy consumption and CO2 emissions.

The average energy efficiency of passenger and freight transport is determined by the fleet composition (number and type of vehicles), vehicle utilisation (occupancy rates and load factors) and driving characteristics (speeds, distances).
In the case of freight transport, energy use per tonne-kilometre also depends on the characteristics of the goods transported (e.g. weight and volume of goods). Thus, differences in the goods transported can result to differences in the energy efficiency, expressed as energy use per tonne-kilometre.
This indicator has been selected to monitor the energy efficiency of the various passenger and freight transport modes enabling thus the evaluation of related policies and targets set at the national and international levels.

Scientific references:

Indicator definition

Specific CO2 emissions are defined as emissions of CO2 per transport unit (passenger-km or tonne-km), specified by mode (road, rail, inland, maritime, air).

CO2 emissions from new passengers cars are expressed in terms of grams of CO2 per kilometer. They are the experimental data measured in the vehicle type approval procedure.


For passenger transport, specific CO2 emissions are expressed in g per passenger-kilometre.
For freight transport, specific CO2 emissions are expressed in g per tonne-kilometre.

For new passenger cars, tailpipe emissions are expressed in g per kilometre

Policy context and targets

Context description

Since specific CO2 emissions are expressed per transport unit, occupancy rates and load factors have a considerable effect on specific emissions produced from passenger and freight transport respectively. Reduction of specific emissions can be achieved by increasing occupancy rates and load factors and/or by decreasing the emissions per vehicle-km (e.g. by setting stricter emission standards and introducing more energy efficient technologies such as hybrid, plug-in hybrids, electric vehicles, etc).


There are no specific objectives or targets related to the energy efficiency or specific CO2 emissions. Policy objectives are only set with respect to CO2 emissions of passenger cars and light commercial vehicles. Regulation No 443/2009 specifies that each vehicle manufacturer must achieve a fleet-average CO2 emission target of 130 g/km by 2015 for all new cars registered in the EU. In order to meet the CO2 emission target of 120 g/km, a further reduction of 10 g/km is to be provided by additional measures, such as the use of biofuels. The regulation also defines a long-term target of 95 g/km to be reached from 2020. Similarly to passenger cars, the Vans Regulation (No 510/2011) specifies a fleet-average CO2 emission target of 175 g/km to be phased in between 2014 and 2017 for newly registered vans in the EU. A long-term target of 147 g/km is specified for the year 2020.

As an additional incentive for the introduction of more energy efficient technologies (hybrid, plug-in hybrids, electric vehicles, electric vehicles with range extender), vehicles of CO2 emissions below 50 g/km receive super-credits. For passenger cars, each such vehicle is counted as 3.5 cars in 2012 and 2013, as 2.5 cars in 2014, 1.5 cars in 2015, and as 1 car from 2016. For vans, each such vehicle is counted as 3.5 cars in 2014 and 2015, as 2.5 cars in 2016, 1.5 cars in 2017, and as 1 car from 2018.

Related policy documents

  • 443/2009
    Regulation (ec) no 443/2009 of the European parliament and of the Council setting emission performance standards for new passenger cars as part of the community's integrated approach to reduce CO2 emissions from light-duty vehicles.
  • Decision No 1753/2000/EC, CO2 from new passenger cars
    Decision No 1753/2000/EC of the European Parliament and of the Council of 22 June 2000 establishing a scheme to monitor the average specific emissions of CO2 from new passenger cars
  • REGULATION (EU) No 510/2011
    REGULATION (EU) No 510/2011 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL setting emission performance standards for new light commercial vehicles as part of the Union's integrated approach to reduce CO 2 emissions from light-duty vehicles

Key policy question

Are the various passenger and freight transport modes becoming more energy efficient?

Specific policy question

Are the new passenger cars becoming more energy efficient?


Methodology for indicator calculation

For passenger transport, the specific emissions are calculated by dividing the CO2 emissions of each mode (i.e. road, rail, maritime and air transport) by the respective passenger-kilometres.
For freight transport, the specific emissions are calculated by dividing the CO2 emissions of each mode (i.e. road, rail, inland shipping and maritime transport) by the respective tonne-kilometres.

For CO2 emissions from new passenger cars, data is compiled from DG-Clima monitoring 2000-2009 whereas the EEA is monitoring it since 2010.

Methodology for gap filling

Passenger- and tonne-kilometres and CO2 emissions are modelled and therefore no gap filling is necessary.

Methodology references

  • TREMOVE documentation TREMOVE documentation
  • EC4MACS model Key data of the EC4MACS transport scenarios: Key data / Transport activities / Vehicle fleet by vehicle category, 2000-2030

Data specifications

EEA data references

External data references

Data sources in latest figures


Methodology uncertainty

COPERT 4 is used for emissions calculations in EC4MACS. CO2 emissions are consistent with UNFCCC submissions.

Data sets uncertainty

Since the data on CO2 emissions, passenger-km and tonne-km are modelled rather than measured, the data must be treated as estimates. Data on CO2 emissions are less uncertain, as they are calibrated against statistical fuel consumption. Hence, the uncertainty of the passenger-km and tonne-km characterises the overall uncertainty of the indicator. EC4MACS is little sensitive when calculating vehicle and tonne kilometres. This means that the overall uncertainty of passenger-km and tonne-km (as a modelled output) depends on the uncertainty of the underlying statistical data provided as input to the model. The latter may vary significantly among different countries, depending on the way data are collected and reported.

Rationale uncertainty


Further work

Short term work

Work specified here requires to be completed within 1 year from now.

Long term work

Work specified here will require more than 1 year (from now) to be completed.

General metadata

Responsibility and ownership

EEA Contact Info

Cinzia Pastorello


European Environment Agency (EEA)


Indicator code
TERM 027
Version id: 1
Primary theme: Transport Transport


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Frequency of updates

Updates are scheduled once per year in October-December (Q4)


DPSIR: Pressure
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)

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European Environment Agency (EEA)
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