Quantifying Hydroplaning Risk: Insights from Water Film Thickness Measurements on Maryland Highways

<div>Wet pavement conditions during rainfall present significant challenges to traffic safety by reducing tire–road friction and increasing the risk of hydroplaning. During high-intensity rain events, the roadway pavement tends to accumulate water, forming a film that can have serious implications for vehicle control. As the longitudinal speed of the vehicle increases, a water wedge forms in front of the tire, leading to partial loss of contact with the road. At critical hydroplaning speed, a complete water layer forms between the tire and the road. Although less common, dynamic hydroplaning poses severe risks when high-intensity rainfall coincides with high vehicle traveling speed, leading to a complete loss of control over vehicle steering capabilities. This study advances hydroplaning research by integrating real-world data from the Road Weather Information System (RWIS) with an existing hydroplaning model. This approach provides more accurate hydroplaning risk assessments, emphasizing the importance of adapting predictive models to real-world conditions. Measurements of water film thickness from two Maryland locations over a year showed values of the water film heights up to 1.9 mm, with significant hydroplaning risk for vehicles with worn tires traveling at highway speeds. Using models such as Gengenbach and Gallaway, the study computes critical hydroplaning speeds, highlighting the importance of tire tread depth, inflation pressure, and pavement texture. Results indicate that the critical hydroplaning speed varies significantly based on these factors, emphasizing the need for safe driving practices during heavy rainfall. The findings underscore also the importance of developing new hydroplaning models in the context of future autonomous vehicles that needs robust algorithms for operating in wet conditions.</div>