PROPOSED DESIGN GUIDELINES FOR REDUCING HYDROPLANING ON NEW AND REHABILITATED PAVEMENTS

This digest summarizes proposed design guidelines for reducing hydroplaning on new and rehabilitated pavements developed in NCHRP Project 1-29, "Improved Surface Drainage of Pavements." In this study, and in the PAVDRN computer program, tread depth was assumed to be 3/32 in. (2.38 mm) and tire pressure was assumed to be 24.0 psi (16.75 kPa). These values were selected because the data that were available to the authors for extending the range of the hydroplaning algorithm used in PAVDRN were also based on these assumptions. Four key areas need to be considered in order to analyze and eventually minimize the potential for hydroplaning. These areas are environmental conditions, properties of the pavement surface, geometry of the roadway surface, and the use of drainage appurtenances. Each of these areas and its influence on the resulting hydroplaning speed of the designed section is discussed in detail in this digest. Five geometric design sections, one for each of the basic geometric configurations used in highway design, are considered in the proposed design guidelines: tangent, curve, transition, crest vertical curve, and sag vertical curve. Finally, the use of drainage appurtenances is reviewed. Drainage appurtenances considered include longitudinal edge drains, slotted drains located between travel lanes, and transverse drains.