Quantifying the Economic Impact and Infrastructure Needs for the French Scenarios Aiming for a 75% Reduction in GHG Emissions by 2050

Quantifying the Economic Impact and Infrastructure Needs for the French Scenarios Aiming for a 75% Reduction in GHG Emissions by 2050


Y Crozet, H G Lopez-Ruiz, Laboratoire d'Economie des Transports, FR




In 2008, three long term scenarios where built by LET-ENERDATA. The said scenarios depicted what the French government?s objective of dividing greenhouse gas emissions by four, from the 1990 level, by 2050 meant in terms of technology and organizational needs. Furthermore, these scenarios did not include a full economic assessment leaving two questions unanswered: Are these ambitions out of our reach? What will the price to pay for this objective be? New research into these questions will let us give a clear answer.


In order to build the LET-ENERDATA scenarios, we put in place a long-term backcasting transport demand model (TILT, Transport Issues in the Long Term). This model is centered on defined behavior types -in which the speed/GDP elasticity plays a key role- in order to determine demand estimations. Presently, this model has been enriched to also be able to asses the needs in infrastructure and the economic impact of different public policies.

Therefore, the TILT model lets us understand past tendencies (the coupling between growth and transport on the urban, regional and interregional scales) and allows us to asses demand for transport services in the long term; trade-offs linked to transport policies on different geographical scales and what these changes entail in matters of infrastructure needs and economic structure.

In this manner, TILT gives us great flexibility concerning the analysis of different public policies and their link to demographic, behavioral and economic change. Thus, by modifying behavioral hypothesis in the model, TILT shows how we can approach the 75% reduction objective whilst assessing the effects on transport demand, infrastructure and the economy.


The main results are a clear view of what choices the public decider has in matter of public policy. Each scenario represents a clear and coherent set of policy pathways that are linked to the economic and infrastructure needs that are inherent to each option. Accordingly, each scenario will detail information concerning:

- Policy pathways and their mechanism of action on behavior and the economy
- A GHG emissions estimation for the transport sector taking into account changes in technical progress, transport demand and public policy.
- An assessment of infrastructure needs linked to the technico-organizational changes envisaged in each scenario.
- An estimation of the economic impact inherent to the different options at hand.

These scenarios let us bring to light -in an applied and simple manner- the different tendencies, counter-tendencies as well as geographical and modal trade-offs present in the long term planning of the transport system. What is more, we associate the results of each scenario to investment and technological needs as well as their economic implications.


The LET-ENERDATA scenarios showed that it is possible to divide greenhouse gas emissions in the transport sector by 4 and that technical progress is able to lead to more than half of these reductions (factor 2). This new study will detail the different policy pathways that lead to the objective and will analyze the varied economic repercussions that they entail.


Association for European Transport