Highway Cross-Sectional Design and Maintenance to Minimize Hydroplaning

Abstract

Highway pavement cross slope is a crucially important cross-sectional design element to properly drain water on highways and improve driver safety by reducing the potential for vehicle hydroplaning. This research estimates the potential of hydroplaning with regard to water depth, and a range of vehicle speed, tire tread depth, tire pressure, pavement surface texture, and cross slope. The research uses a sensitivity analysis of mathematical models developed previously to estimate hydroplaning potential for different inputs. The range of inputs includes conservative values from a road user standpoint (e.g., high vehicle speeds, low tire pressure, and nearly bald tires) in combination with minimum design criteria (e.g., pavement surface texture and cross slope). The benefits of higher cross slopes and open graded friction course surface textures is also considered. A range of rainfall intensity inputs are included in the analysis; however, intensities greater than 76.2 mm/h (3 in./h) are not of significant concern from a hydroplaning standpoint because the lack of visibility tends to cause even the most aggressive drivers to slow down well below critical speeds. The paper includes a series of tables and figures that state highway agencies can use to help assess hydroplaning potential based on roadway pavement and cross-sectional design characteristics.