Slush and Aquaplaning Rainwater that lingers in the ruts of roads places demands on driving. When the ruts are deep, the risk of hydroplaning is high, but anticipatory driving and good treads can reduce the risk. New tires are the best weapons against hydroplaning. A tread pattern that channels water out from between the tire and the road is the most effective means of preventing hydroplaning. According to test results, hydroplaning starts at 76 km/h (47 mph) when cornering on worn out tires (groove depth below 1.6 mm), whereas the corresponding speed for new tires is 96 km/h (60 mph).