Determination of rates of occurrence for hydroplaning events with naturalistic driving data

Introduction: The degree to which hydroplaning occurs in real-world conditions is not entirely known. Naturalistic driving data can be helpful in addressing some of the limitations of existing data sources related to the incidence of hydroplaning. Method: Data from the Second Strategic Highway Research Program Naturalistic Driving Study were leveraged to estimate the incidence of hydroplaning. Two hydroplaning detection algorithms were used for candidate hydroplaning event generation. Hard braking events were also identified and analyzed as normative comparisons to the hydroplaning events. Results: A total of 1,141 hydroplaning events were found in the naturalistic driving data and utilized for analysis, including 650 hydroplaning events that were unnoticeable by the driver based on lack of observable reactions, 13 events that were deemed to be of “critical” severity, and only 3 events that resulted in crash events during more than 30 million miles of driving. Hard braking events occurred nearly four times more often, and at comparatively lower speeds, than hydroplaning events. Observable driver reactions also differed between event types. For example, more drivers changed their posture after a hydroplaning event than after a hard braking event and drivers maintained both hands on the wheel at higher rates after experiencing a hydroplaning event than after a hard braking event. Suspension of secondary tasks during hard braking and hydroplaning events was also observed. Conclusions: Overall, these findings suggest that drivers perceive hydroplaning events as more harmful than hard braking events, despite the large discrepancy and incompatibility in how often these driving situations lead to vehicular crashes. Practical application: The findings of this research will provide vehicle and tire designers with empirical data that quantifies the important tradeoffs they must make in balancing vehicle and tire performance in wet and dry environments, and in tradeoffs related to tire wear performance and grip.