Research and Development Intensity, Industrialization, Energy Consumption and Auto Transport Activity: Long-Run Evidence from EU-26 Countries

Road freight transport is a cornerstone of the European Union’s logistics system, accounting for approximately three-quarters of inland freight activity while consuming a substantial share of transport energy. Despite extensive research on economic growth and environmental decoupling, the relationships between research and development (R&D) intensity, industrial activity, energy consumption, and road freight performance remain insufficiently explored using heterogeneous panel methods. This study investigates the long-run associations between R&D intensity, road transport energy consumption, industrial activity, trade openness, urbanization, and road freight transport activity, measured in million tonne-kilometres performed by vehicles registered in each reporting country, across 26 EU member states from 1999 to 2024. The empirical framework employs Common Correlated Effects Mean Group (CCE-MG) and Augmented Mean Group (AMG) estimators, Method of Moments Quantile Regression (MMQR), and Dumitrescu–Hurlin panel Granger non-causality tests. Diagnostic results confirm cross-sectional dependence, slope heterogeneity, mixed orders of integration, and panel cointegration. The findings reveal robust positive associations between road energy consumption, industrial activity, and freight performance, with the energy coefficient approaching unity at upper conditional quantiles, indicating a persistent coupling between energy use and freight activity. R&D intensity exhibits a negative association, particularly at higher quantiles, suggesting potential efficiency gains and logistics optimization. Trade openness displays heterogeneous associations, shifting from negative coefficients at lower quantiles to positive coefficients at upper quantiles, whereas urbanization is positively associated with freight activity primarily at lower quantiles. Robustness checks confirm the stability of these patterns. Panel Granger tests indicate unidirectional Granger-predictive relationships running from R&D intensity, industrial activity, and trade openness to freight activity, alongside a bidirectional Granger-predictive relationship between energy consumption and freight performance, which reflects predictive directionality rather than structural causation. The findings underscore the importance of energy decarbonization, technological advancement, and differentiated freight policies in reconciling logistics competitiveness with European Green Deal objectives.