Cruise control

This is about a woman who activated her cars’ cruise control when she was driving in the rain. According to this story, her car suddenly began to hydroplane and literally flew through the air. Then the police officer, who attended the crash, told her that she should never activate the cruise control when driving on wet roads. The explanation given was that when the wheels of a vehicle spin when it lost traction would make the engine increase power and speed the vehicle up.

This is not factually correct. Cruise control systems use sensors located inside the gearbox to read the speed and not on the wheels. When the wheels spin freely, (like when hydroplaning), the sensors would pick up that the engine revolutions have increased, and immediately reduce power. Hydroplaning occurs when a tyre loses grip due to a layer of water between the road surface and the tyre itself.

However, we do not recommend activating the cruise control for other reasons. When driving in adverse weather, there are more demands on a driver, like lack of visibility, slippery roads, driver fatigue setting in much faster, etc. Roads are most slippery when it starts to rain after a long dry period. Due to the reduced visibility, it may take longer to react to situations and the critical response time may increase significantly.

The cruise control may disengage slower than it takes a (normal) driver to react when the driver takes his/her foot off the accelerator.

What can you do to make it safer on the road? Start by turning on the headlights on dipped beam – NO Parking lights please! Slow down a bit. The speed limit is not a target; therefor one should only drive at the limit when driving conditions are exceptionally good. Increase your following distance to at least four seconds. Keep your vehicle well maintained. Tyre threat at least 3mm, wiper blades are in good nick, all lights are working and windows are clean.

I will also recommend using a reputable water repellent on the outside of the glass. Something like Rain-X you can buy at most auto- or hardware dealers.

Safer Journeys!

Daniel Naudé