Environmental assessment of urban mobility: combining life cycle assessment with land-use and transport interaction modelling – application to Lyon (France)

Abstract

In France, greenhouse gas (GHG) emissions from transport have grown steadily since 1950 and transport

is now the main source of emissions. Despite technological improvements, urban sprawl increases the

environmental stress due to car use. This study evaluates urban mobility through assessments of the

transport system and travel habits, by applying life cycle assessment methods to the results of mobility

simulations that were produced by a Land Use and Transport Interactions (LUTI) model. The environmental

impacts of four life cycle phases of urban mobility in the Lyon area (exhausts, fuel processing,

infrastructure and vehicle life cycle) were estimated through nine indicators (global warming potential,

particulate matter emissions, photochemical oxidant emissions, terrestrial acidification, fossil resource

depletion, metal depletion, non-renewable energy use, renewable energy use and land occupancy). GHG

emissions were estimated to be 3.02 kg CO2-eq inhabitant−1 day−1 , strongly linked to car use, and indirect

impacts represented 21% of GHG emissions, which is consistent with previous studies. Combining life

cycle assessment (LCA) with a LUTI model allows changes in the vehicle mix and fuel sources combined

with demographic shifts to be assessed, and provides environmental perspectives for transport policy

makers and urban planners. It can also provide detailed analysis, by allowing levels of emissions that

are generated by different categories of households to be differentiated, according to their revenue and

location. Public policies can then focus more accurately on the emitters and be assessed from both an

environmental and social point of view.