Energy Indicators for Sustainable Development: Guidelines and Methodologies International Atomic Energy Agency United Nations Department of Economic and Social Affairs International Energy Agency Eurostat European Environment Agency

(c) Limitations of the Indicator: Data availability may limit the disaggregation of 
the indicator to the desired level. Considerable work is often required to disaggregate 
energy balances into various modes of transport. 
Some countries’ transport energy statistics include fuel consumed by domestic airlines 
or shipping lines in international transport. Efforts should be made to exclude such 
transport and energy use from the indicators. 
Measurement and interpretation of energy intensities are complicated by differences 
among products within a category, such as size (e.g. automobile weight), features 
(power steering and automatic transmission in automobiles) and utilization (vehicle 
occupancy if passenger-km is the measure of output). 

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(d) Alternative Definitions/Indicators: An alternative, simpler measure of energy 
intensity for transport could be overall average fuel consumption per passenger-km or 
tonne-km for all modes, but the results would be strongly influenced by the mix of 
modes and vehicle types, which varies enormously among countries and over time. 
ASSESSMENT OF DATA 
(a) Data Needed to Compile the Indicator: 
• Energy use by mode of transport, vehicle type and fuel for passenger travel 
and freight transport separately. 
• Distance travelled by vehicles, passengers and freight, including load factors. 
• Distance travelled by urban public transport and corresponding share of 
electric vehicles. 
(b) National and International Data Availability and Sources: National energy 
balances and energy statistics from the International Energy Agency (IEA) and 
Eurostat normally do not disaggregate road transport into individual means of 
transport, but this information is sometimes published by transport ministries. Few 
sources of energy data separate fuel consumption for air, rail or domestic shipping 
into that for passengers and that for freight, but national or private rail and shipping 
organizations may have this information. Energy use for local electric transport 
(commuter rail, metro, trams) is often published separately by national authorities. 
Eurostat, the European Conference of Ministers of Transport (ECMT) and the United 
Nations Economic Commission for Europe (UNECE) are leading agencies for the 
collection of data on vehicle-, passenger- and tonne-km in Europe. Transport 
ministries in the United States, Canada, Japan, Australia and other countries publish 
similar data, often through their statistical agencies. In developing and transitional 
countries, fewer data are available.