International Industrial Ecology Day 2021

Freight statistics are at the core of many studies in the field of industrial ecology because they depict the physical interdependencies of territories and allow links to be made worldwide between production and consumption. Recent studies have focused increasingly on subnational scales, often relying on domestic freight data. In this perspective, we analyzed the uncertainties of the French domestic road freight survey, road being by far the most common mode of transport in the country. Based on a statistical analysis of the survey, we proposed a model to estimate the uncertainty of any given domestic road transport flow. We also assess uncertainty reduction when averaging the flows over several years, and obtain for instance a 30% reduction for a three-year average. We then study the impact of the uncertainties on regional material flow studies such as the economy-wide material flow analysis of the Bourgogne region. Overall the case studies advocate for a systematic assessment of freight uncertainties, as neither the disaggregation level nor the quantities traded are good enough predictors. This justifies the need for an easy-to-implement estimation model. Finally, basic comparison with the German and Swedish surveys tends to indicate that our conclusions are likely to be valid in other European countries.