Historically the environmental impact has included:
From 1970ties: Hazardous emissions with impact on health, such as NOx, hydrocarbons and particulates
From 1980ties: Sulphur as contributor to acid rain, Substances that deteriorate the high altitude ozone layer
From 1990ties: Fossile carbon dioxide and other substances such as methane and nitrous oxide with impact on global warming
From 2000: Energy use and efficiency
The focus is not changing it is including more demands on the transports. The inclusion of energy use is justified by:
-The energy market is global, what is not consumed in one sector can be used in another sector or another part of the world.
-The global energy market is dominated by coal power plants and the marginal energy in general is fossile.
-The best kind of energy is the energy not used. Rather than changing energy carrier* it is of higher value for society to perform the same work with less energy.
*Noting the first law of thermodynamics that energy can not be consumed, just converted to other forms
Therefore, all over the world increasing emphasis is put on the energy efficiency of transports. As a consequence increasing efforts are made to analyse the energy use in society. In a recent french study, by the environmental authority ADEME, the energy use of person transports have been analysed and reported. Click here to reach ADEME
Not surprisingly for many of us the bus comes out as the overall “winner” for regional and intercity traffic in the vicinity of Paris. The high weight of trains increase the energy use. With a modern hybrid bus the difference is even more accentuated.