PAVEMENT AND GEOMETRIC DESIGN CRITERIA FOR MINIMIZING HYDROPLANING

A comprehensive literature review, multistate questionnaire, mathematical modeling, computer simulation, field testing and data correlations were used to establish criteria relating to geometric and pavement surface characteristics to minimize highway hyroplaning. More specifically, the authors have covered in detail the empirical indications of hydroplaning as determined from interpretation of hard data developed with a spindown trailer in a hydroplaning trough, skid number trailers including drag link and torque, and extensive tire and pavement testing under simulated and natural rain. Precise measurements of surface drainage were examined and equations relating pavement texture, cross slope and rainfall were developed. Random and patterned textures covering the complete range of real-world pavements were included. A determination of deficiencies in existing surface drainage design methodology for sag-vertical curves was conducted by state surveys and representative sites were studied and innovative answers supplied. A summary of criteria to reduce hydroplaning is presented along with recommendations for construction of flexible and rigid pavements to minimize hydroplaning. Extensive field studies of open-graded surfaces under simulated and natural rain confirm the high level performance of such surfaces, including tire-to-surface contact, reduction of splash and spray, and flatter friction vs. speed gradients. Report No. FHWA-RD-79-30 is a technical summary of this report. (FHWA)