Hydroplaning

Texas bus crash

Driver Loses Control

It was still raining last Saturday morning when they recovered the bus on Highway 83 in Webb County, Texas.

The bus was northbound when it lost control and when off of the road, resulting in eight fatalities and dozens injured. One factor that National Transportation Safety Board investigators will look at is if hydroplaning contributed to the rollover.

What is Hydroplaning?

To look at loss of traction, it helps to first look at a tire’s grip or traction. Every tire has a footprint or “patch” where it meets the road.

tire patch

Anytime something comes between the tire and the road — snow, ice, rain, loose gravel, — there are fewer pressure points and less contact with the road.

But there is more to it than just that. The tire needs to be properly inflated (and that information is specified by the vehicle manufacturer — not on the side of the tire). The tire also needs to have adequate tread depth (in bad weather conditions, this is more than the legal minimums of 4/32-inch on front tires and at least 2/32-inch on other tires).

Finally, the driver needs to know what they are doing. Getting into trouble is the easy part. Preventing a small problem from turning into a major disaster or a catastrophe is the true measure of a driver’s level of skill. Sometimes this means not driving at all . . .

The tire patch, proper tire inflation, adequate tread depth and driver skill level all contribute their part to whether or not a vehicle can be safety driven depending on weather conditions. A good patch but no tread depth can be as bad having a good tread depth but under– or over–inflated tires, etc.

Hydroplaning is the loss of control by a driver when their vehicle’s tires ride on a thin film of water over the road.

Conditions for hydroplaning can be expected where water or other precipitation accumulates to a depth of one tenth of an inch or greater, especially at speeds greater than 45 MPH.

Bad road design can result in improper water runoff. The most frequent lawsuit in the state of South Caroline against the DOT is for hydroplaning. The state has paid out millions is claims over the years. One reason cited by SC DOT officials is water sometimes cannot run off due to thatching of grass alongside the roadway.

So depending on how fast a vehicle is going and the depth of water, on the roadway, the vehicle can ride up on the film of water, becoming unstable or even impossible to control. The vehicle is then hydroplaning.

Hydroplaning Countermeasures

• Listen for a sloshing sound from the wheel wells.

• Look for pools of water forming on the road.

Slow down when it starts to rain.

• Turn off the cruise control.

Don’t drive in heavy rainfall, if you can safely park.

Drive smoothly: no sudden turns or braking.

• Keep tires properly inflated with plenty of tread.

• Take a skid-school course for your class and type of vehicle.

The key to prevent loss of control due to hydroplaning is to read the roadway. And be ready for that ‘Someday.’

Thank you for reading this.