Assessing modal shifts on a macroscopic scale

The demand for road freight transport in Europe is expected to increase in the future. All modes are equally supposed to improve their efficiency in order to meet this demand in the best conditions. Proposals to improve the productivity of road transport have thus appeared, one of them consisting in using longer and heavier trucks, up to 25.25 m long and 60 t heavy. The European Commission through its Directorate General for Transport and Environment has commissioned in 2007 a study to investigate the possible effects of changing the directive to allow for longer and/or heavier vehicles in international transport and the methodology presented in this paper was amongst the ones which were used by the consortium to assess, on a macroscopic scale, the modal shifts that would occur if heavier and/or longer vehicles were allowed. This paper presents in details the methodology used to quantify the magnitude of the corresponding modal reports. Direct price elasticities and cross elasticities are used through two different demand functions in order to provide a range of variation in which would stand the modal reports encountered by each mode. Additional assumptions were also made to account for the evolution of these elasticities in time.