**4. Driving factors of transport energy efficiency and policy options**

Before presentation of decomposition methodology, we present and discuss some potential factors which have impacts on transport energy intensity. This is following by policy options to reduce transport energy use.

#### **4.1. Driving factors of transport energy intensity change**

Several factors contribute to change in energy intensity of transport sector. Examples include:

<sup>2</sup> Contrarily to Laspersey method, the advantages of LMDI method are, for example, the residual-free decomposition and the accommodation of the occurrence of zero values in the data set to small positive constant.

urban characteristics on transport energy intensity.

can be attributed to effects of:

Consequently,

include:

shown by (Ang, 2004)2, change in transport energy intensity (Δ*TEI*




Then, effects can be calculated for example for *MMeff* as:

**4.1. Driving factors of transport energy intensity change** 

changes in the named direct factors.

options to reduce transport energy use.



which indicated the demand of energy to produce unit of transport services per mode, *TI* represents transport intensity per mode which indicates the demand of modal transport services to produce unit of GDP, *VI* refers to vehicle intensity and measures the demand of vehicles by mode to produce unit of GDP and *M* refers to rate of motorization. The change in these factors summarizes their direct and indirect impacts on change in transport energy intensity. The indirect impacts pass through the influence of demographic, economic and

Using LMDI method because their advantages comparatively to Laspeyres techniques as

Δ ≡ − ≡ ++++ ( ) () 0 *ijt eff eff eff eff eff TEI RTE T RTE MM EI TI VI M* (9)

Δ≡ − ( ) () ( ) () ( ) () <sup>−</sup> 0 ln / 0 / <sup>0</sup> *ijt TEI TEI T RTE MM T MM TEI T RTE* (10)

Growth of transport-related energy intensity can be analyzed among its sensibility to

Before presentation of decomposition methodology, we present and discuss some potential factors which have impacts on transport energy intensity. This is following by policy

Several factors contribute to change in energy intensity of transport sector. Examples

2 Contrarily to Laspersey method, the advantages of LMDI method are, for example, the residual-free decomposition

and the accommodation of the occurrence of zero values in the data set to small positive constant.

**4. Driving factors of transport energy efficiency and policy options** 

*ijt* ) between two periods




Transport Intensity and Energy Efficiency: Analysis of Policy Implications of Coupling and Decoupling 283

Increase of buying power leads to the growth of private vehicles number and so of personal mobility. Then, transport energy intensity is linking to the level of personal motorization. Rapid growth of both motorization and travelling distance improve energy consumption and gas emission of transport sector. Moreover, increase of motorization in urban areas leads to more urban congestion with which the energy



In this section we derive some policy options which can reduce energy intensity from transport sector and so ameliorate the energy efficiency of transport activity. These policy options aim to reduce coupling factors effects and improve decoupling factors effects. As we have showed, from decomposing analysis, it become possible to determinate the principal contributors of transport energy consumption growth, named driving factors. The analysis of critical factors trends helps to identify the instruments to reduce their effects and so to save energy. From these instruments, it will be possible to elaborate some energy sustainable policies for transport sector. Examples of instruments include technological,

Decoupling the transport energy consumption from economic growth is one of the important solutions if the economic growth is identified as a driving factor. Several practices are suggested in this context and depend on the type of decoupling (relative or absolute decoupling)4. Then many policy options are available to ameliorate the transport sector

4 Decoupling is said absolute if negative externalities are stable or decreasing simultaneously with an economic

3 Urbanized kilometers measure the concentration of population behind the urban road network.

growth. However, it said relative if the growth of negative externalities is less than of economic activity.

significantly to the length of road network and so to use of road mode.

technical, regulatory, fiscal and economic instruments.

intensity will be reinforced for urban transportation.

Kenworthy, 1989).

**4.2. Policy options** 

energy efficiency:


Increase of buying power leads to the growth of private vehicles number and so of personal mobility. Then, transport energy intensity is linking to the level of personal motorization. Rapid growth of both motorization and travelling distance improve energy consumption and gas emission of transport sector. Moreover, increase of motorization in urban areas leads to more urban congestion with which the energy intensity will be reinforced for urban transportation.


#### **4.2. Policy options**

282 Energy Efficiency – The Innovative Ways for Smart Energy, the Future Towards Modern Utilities

which consumes less of energy.






the use of transport services and lead to growth of energy intensity.

of clean vehicles use and comportment of driving behaviour.

of injected supplementary vehicles.

In this section we derive some policy options which can reduce energy intensity from transport sector and so ameliorate the energy efficiency of transport activity. These policy options aim to reduce coupling factors effects and improve decoupling factors effects. As we have showed, from decomposing analysis, it become possible to determinate the principal contributors of transport energy consumption growth, named driving factors. The analysis of critical factors trends helps to identify the instruments to reduce their effects and so to save energy. From these instruments, it will be possible to elaborate some energy sustainable policies for transport sector. Examples of instruments include technological, technical, regulatory, fiscal and economic instruments.

Decoupling the transport energy consumption from economic growth is one of the important solutions if the economic growth is identified as a driving factor. Several practices are suggested in this context and depend on the type of decoupling (relative or absolute decoupling)4. Then many policy options are available to ameliorate the transport sector energy efficiency:

<sup>3</sup> Urbanized kilometers measure the concentration of population behind the urban road network.

<sup>4</sup> Decoupling is said absolute if negative externalities are stable or decreasing simultaneously with an economic growth. However, it said relative if the growth of negative externalities is less than of economic activity.

*Logistic solutions*, such as relocation of production units, multimodality, intermodality, optimization of the entire transportation chain from origins to final delivery and rescheduling of transport operations for companies are some examples of instruments which aim to reduce the travelling distances but not transported tons.

Transport Intensity and Energy Efficiency: Analysis of Policy Implications of Coupling and Decoupling 285

*Regulatory instruments* can be also help to improve the transport sector energy efficiency. Restrictions of older road vehicles importation and encouragements of vehicle fuel economy standard can be use as successful tools to reduce energy intensity. Additionally, control of leasing credits given to road freight companies and particular credits for personal cars could

*Technological instruments* have shown their positive impacts on vehicle energy efficiency. Research and development have given several technologies which aim to reduce energy consumption of vehicles. Fuel economy can be realized by ameliorating of energy efficiency of drive train. So, new technologies which applied on the power of vehicle's engine could ameliorate the engine efficiency. Moreover, fuel economy increase also with reducing of the amount of energy necessary to move the vehicle. New technologies used to reduce vehicle weight and rolling resistance permit to increase energy efficiency. We should be note that these technologies are more accessible for developed countries and more expansive for

As stated at the beginning of this chapter, the relationship between economic growth, transport activity and energy consumption is analyzed by more existing studies. In this chapter, majority of methodologies used to study energy efficiency for transport sector has been examined. From the sustainable transport point of view, there are large set of factors which influence transport sector energy consumption. All these factors are defined in the contexts of coupling and decoupling relationship between transport development and

Ameliorating of transport sector energy efficiency depends on economic, urban, technological and fiscal factors. Decisions in land use planning and transport planning, prices and quality of fuels, taxes and subsidizes and investments on new technologies have a significant impacts on control of energy efficiency from transport sector and their environmental effects. However, in developing countries, improving the energy efficiency in transport sector requires more attention by government authorities, investors and civil society. Policymakers in these countries give more importance to transport accessibility to population and search to satisfying the economic growth in term of freight transport

*Higher Institute of Transport and Logistics of Sousse, University of Sousse, Sousse, Tunisia* 

Agras J., and Chapman, D., 1999. A dynamic approach to the environmental Kuznets curve

reduce road vehicles demand and improve public transport demand.

developing countries.

**5. Conclusion** 

economic growth.

**Author details** 

**6. References** 

Rafaa Mraihi

without any policy of energy economy.

hypothesis. *Ecological Economics*, 28, 267-277.

*Modal shifting* is also a decoupling instrument which aims to improve the demand of less energy-intensive modes of transport. In the large majority of countries, road transport is the predominant mode. It has often the important share in transport sector fuel consumption. To reduce its energy intensity, authority should shift over to rail mode. To this end some tools should be applied, for examples, reinforcing of rail infrastructures, the amelioration of services quality (availability, speed, regularity, tariffs, security, accessibility) and subsidizes for users of rail services.

*Economic structure change* which increases the share of service sector in the GDP can reduce transport intensity and so ameliorate the energy efficiency of transport sector. Volume of physical production and its movements from production market to consumption market have a determining influence on travel distances. When economic growth is driving especially by tertiary sector and trucks with high transportation capacities are used for freight transport, travels can be reduced and energy necessary to satisfying the demand of economic growth in term of transportation can be also reduced.

*Transport planning* can be reduce personal mobility and reduce distances especially in urban areas. It should be adopted by local authorities in order to make sustainable their transport system. Shifting over public transport is one of the important solutions of urban transport planning. Ameliorating supply and quality of public passengers transport could reduce personal motorization. Developing of public transport network by extension of public transport lines and through integration of private investment could be improving the public transportation. Moreover, revising the spatial distribution of households and activities in order to reduce travels can be deteriorating the urban density, the urbanized kilometers number and so road transport-related energy consumption in urban areas. New equity in term of spatial repartition of activities between all cities could reduce the concentration of populations and economic activities in megacities and so urbanized kilometers.

*Fiscal and economic instruments* could ameliorate the transport energy efficiency. They can be use to encourage the shifting over to energy efficient mode and the switching to clean fuels. In order to ameliorating the vehicle fuel efficiency and so reducing the vehicle fuel intensity, governments can impose some fiscal instruments. For examples, taxation of fossils fuels for personal cars use can increase the personal fuel expenditures and so encouraging the substitution of collective transportation to individual transportation. In addition, fossil fuel taxes for road freight transport could encourage the companies to promote the use of vehicle with high capacities transportation and less energy consumption. These taxes could be applied along with subsidies given for users of renewable energy. Government can also apply economic instruments, such as the increase of diesel and gasoline prices in order to substitute of the clean fuels to fossil fuels.

*Regulatory instruments* can be also help to improve the transport sector energy efficiency. Restrictions of older road vehicles importation and encouragements of vehicle fuel economy standard can be use as successful tools to reduce energy intensity. Additionally, control of leasing credits given to road freight companies and particular credits for personal cars could reduce road vehicles demand and improve public transport demand.

*Technological instruments* have shown their positive impacts on vehicle energy efficiency. Research and development have given several technologies which aim to reduce energy consumption of vehicles. Fuel economy can be realized by ameliorating of energy efficiency of drive train. So, new technologies which applied on the power of vehicle's engine could ameliorate the engine efficiency. Moreover, fuel economy increase also with reducing of the amount of energy necessary to move the vehicle. New technologies used to reduce vehicle weight and rolling resistance permit to increase energy efficiency. We should be note that these technologies are more accessible for developed countries and more expansive for developing countries.
