Hydroplaning control on multi-lane freeways

Adverse weather–induced wet pavement conditions represent a critical factor in roadway safety resulting from aquaplaning, especially on high-speed facilities. This study explores the dynamic aquaplaning phenomenon on wide 4-lane freeway sections, aiming to determine critical thresholds for water film thickness (WFT) above the pavement macrotexture and aquaplaning speed (APS). A total of 75 four-lane freeway sections designed in accordance with the 2008 German urban motorway design guidelines for EKA 3 classification were analyzed. These alignments were combined with a selected range of additional parameters, based on balanced literature findings, involving pavement surface characteristics, vehicle, and user parameters, as well as various rainfall intensity rates, resulting in 6075 combinations in total. Aquaplaning was assessed using Gallaway’s method, enhanced with the drainage path calculated as the algebraic sum of the longitudinal grade and superelevation in the 3D roadway geometry. The existing literature on aquaplaning has primarily focused on roadway sections with constant longitudinal grades and cross slopes. A key contribution of the present research is the investigation of aquaplaning risk within superlevation transition zones, where the drainage path length can become substantially longer than in conventional sections. This condition may lead to increased water accumulation and different pavement drainage characteristics, making superlevation transitions a critical yet relatively underexplored aspect of aquaplaning analysis. Multiple linear regression analysis showed high predictive accuracy for both WFT and APS. From a road geometry perspective, only grade values were found to be statistically significant. Beyond grade, the statistical analysis highlighted the influence of rainfall intensity and pavement texture depth, while tire pressure and tire tread depth were also shown to be significant factors for WFT and APS assessments, respectively. The findings provide technical support for roadway design and speed management, helping to identify conditions under which variable speed limits may be effectively implemented to enhance safety.