What Causes Hydroplaning and How to Prevent It

Driving slower in rainy weather and replacing worn tires are the most effective ways for drivers to reduce the risk of hydroplaning, according to a study from the University of Georgia published in Applied Sciences. The research indicates that while water depth and road texture influence vehicle grip, speed is the primary factor drivers can control to prevent tires from lifting off the pavement.

The Federal Highway Administration estimates that severe weather and wet pavement contribute to approximately 6,000 deaths and 500,000 injuries annually. Hydroplaning occurs when water accumulates on a road surface, causing tires to lose their grip and slide.

To analyze the phenomenon, researchers used a combination of computer simulations and live field tests. They utilized a mechanism to adjust tire speed and water volume on a track, using sensors to measure the specific forces that lead to a loss of traction.

How Water Depth Affects Tire Traction

The University of Georgia study found a non-linear relationship between water thickness and hydroplaning risk. Initially, as water depth increases, the likelihood of hydroplaning rises. However, the researchers observed that once water reaches a depth of approximately 10 millimeters, the risk begins to fall steadily.

Researchers suggest this occurs because thinner layers of water are more difficult for tires to break through, which hinders the tire’s ability to maintain contact with the road. In deeper water, the highest risk occurs at the moment the tires first hit the wet pavement, before the tires can effectively disperse the water.

As the tires push the water away, the risk of hydroplaning decreases. This suggests that the initial impact with a deep pool of water is the most critical moment for vehicle stability.

The Role of Speed and Vehicle Design

Speed remains one of the most critical risk factors when road conditions are constant. As a vehicle accelerates, the water on the track exerts more pressure on the tires, eventually lifting them off the road surface.

“It’s very similar to an airplane. You reach a certain speed, and the vehicle lifts,” Linbing Wang, corresponding author of the study and a professor in the University of Georgia College of Engineering, said.

Beyond speed, the study identified several other contributing factors to hydroplaning risk:

• Tire tread patterns
• Tire pressure
• The surface texture of the road
• The ability of the road to drain water

Infrastructure and Preventative Measures

While drivers can control their speed and tire maintenance, the researchers noted that infrastructure plays a significant role in safety. The study highlights Georgia’s use of a thin surface layer of pavement on highways, which allows water to drain through the asphalt instead of pooling on the surface.

“Speed is something that drivers can control. The pavement texture and raining thickness you cannot control,” Wang said. “Human factors affect safety. That’s something we should all be concerned about.”

Wang stated that a better understanding of these contributing factors allows for improvements in both pavement and vehicle design to save lives.