Aquaplaning
aquaplaning (more rarely, aquaplaning or hydroplaning) is the situation in which a vehicle crosses on the road at a certain speed a surface covered with water, leading to a loss of traction and control of it by the driver. If this were to happen to all of the wheels, the vehicle becomes, in effect, an uncontrollable sled.
It is important to differentiate hydroplaning from the effect that water produces by merely acting as a lubricant. Traction decreases on wet pavement even when hydroplaning is not occurring.
One such example would be the 2014 Japanese Grand Prix when Jules Bianchi failed to evacuate the water causing a red flag and fatal crash.
Causes
Any function of a vehicle intended to change its direction or speed depends on the friction between the tires and the ground surface to act. The grooves in the deck are designed to evacuate any water that might be underneath, increasing friction and ensuring control. Aquaplaning occurs when, for various reasons, the roof encounters more water than it is capable of removing. The pressure of the water in front of the roof forms a wedge under it, lifting it off the pavement and reducing or eliminating friction. The wheel then begins to skid on the surface of the water with little or no contact with the pavement, drastically decreasing control and braking ability. The vehicle, once hydroplaning, will skid until it collides with an obstacle or until its speed decreases enough for the wheels to recontact the ground surface and friction is restored. The risk of hydroplaning increases with the depth of the water layer and the sensitivity of the vehicle to it.
Factors that affect the depth of water
- Surcs on the road: Heavy vehicles can form longitudinal grooves in the pavement that facilitate the accumulation of water, negatively impacting on the draining of the water.
- The texture of the pavement: The concrete – or concrete in Spain – can be preferable to asphalt, since it is less prone to the formation of grooves by trucks and heavy vehicles. However, it is less rough than the asphalt mixture, a factor that would also decrease traction.
- The degree of transverse convexity and the inclination the way: The road must have a degree of transverse convexity in "U" inverted that allows the correct drainage of the water to the banana. The inclination of the road refers to the degree of longitudinal slope that has the same at a certain point. Vehicles have less tendency to hydroplane by moving uphill and have more tendency to do so by moving downhill between two connected hills, where water tends to accumulate.
- Width the way: The widest paths require a greater degree of cross-sectional convexity to be able to evacuate the water with the same effectiveness.
- La intensity of precipitation.
Factors that affect vehicle sensitivity
- The characteristics of braking, maneuverability and acceleration inherent in vehicle and driver.
- The wear of the covered: Depleted grooves come into hydroplane at lower speeds (5-7 km/h) than those with new grooves.
- Pressure of inflated decks: Deflated or inflated roofs below their optimal capacity are more likely to enter hydroplane than those that are properly inflated (or even above their level). Well-inflated decks help the grooves to efficiently evacuate the water.
- The contact surface with the floor: The contact surface is the area where the deck contacts the pavement. Vehicles with narrow and long contact surfaces are less prone to hydroplane (bikecycles, for example), while those with wide and short-diameter wheels are more.
- The weight of the vehicle: Increased weight on a properly inflated deck, lifts the contact surface and decreases the possibility of hydroplane. However, the weight may have the opposite effect on a deflated wheel.
There is no precise equation for the speed at which a vehicle hydroplans. In general, cars hydroplan at speeds greater than 45 mph (72 km/h), where there is standing water with a depth of at least 2.5 mm for a distance of 30 feet or more.
"Aquaplaning is a very real and unpredictable danger". Accessed May 27, 2015.