Cruise Control In The Rain
There is a bit of facebook “wisdom” floating around. This time, most of the the internet skeptics seem to think it is the truth. Lets begin with the message:
A 36 year old female had an accident several weeks ago. It was raining, though not excessively when her car suddenly began to hydro-planeand literally flew through the air. She was not seriously injured but very stunned at the sudden occurrence!When she explained to the Police Officer what had happened, he told her something that every driver should know – NEVER DRIVE IN THE RAIN WITH YOUR CRUISE CONTROL ON. She thought she was being cautious by setting the cruise control and maintaining a safe consistent speed in the rain…. But the Police Officer told her that if the cruise control is on,your car will begin to hydro-plane when the tyres lose contact with the road, and your car will accelerate to a higher rate of speed making you take off like an aeroplane. She told the Officer that was exactly what had occurred. The Officer said this warning should be listed, on the driver’s seat sun-visor – NEVER USE THE CRUISE CONTROL WHEN THE ROAD IS WET OR ICY, Along with the airbag warning. We tell our teenagers to set the cruise control and drive a safe speed – but we don’t tell them to use the cruise control only when the road is dry.
This message makes intuitive sense. Unfortunately, a lot of other bits of internet wisdom sound good at first, but turn out to be frauds. There is no way to confirm the story of the “36 year old female.” When you are repeatedly lied to, your instinct is to not believe what you are told. In this case, if you google the key phrase, you will find abundant confirmation.
Snopes has numerous critics. In this case, the story is confirmed, and a link supplied to the Insurance Corporation of British Columbia. “Turn off the cruise control: Wet roads can cause wheels to spin and lose control. The only way to stop wheels from spinning and maintain control is to immediately reduce power. An activated cruise control system applies continuous power, keeping the wheels spinning. By the time you disengage the cruise control it may be too late – you may have already lost control.”
Hoax Slayer says the story is true, but “misleading and overly alarmist.” They say the number one problem here is the slower reaction times with cruise control. People typically move the right foot away from the control pedals when CC is used. If there is an emergency, you will react a split second later. HS has a link to Car Point Australia, which makes this point: “This is the key that makes a nonsense of the email. Modern cars take their speedo reading from the driveshaft or transmission. This means the cruise control bases its responses on the speed of the driven wheels, not the car itself. This is an important distinction and fail safe position. If the driven wheels skid because they lose grip, the spinning wheels will cause the speedo to show a higher reading which will force the cruise control to release the throttle faster than most drivers. Regardless of whether the car itself slows down or speeds up, the cruise control will always reduce the throttle no matter what until the driven wheels slow down back to the pre-set speed. If the wheels continue to slip under this scenario, this will always leave the car traveling more slowly relative to the road, not faster as described in the email. “
Truth or fiction and urban legends agree with snopes that this is a real problem. The only dissenting voice seen so far is museum of hoaxes. They give a link to Australia’s Royal Automobile Association, which doesn’t think it is a problem. ” “Should the car’s tyres break traction with the road, such as in an aquaplane situation, the increase in wheel speed would be sensed and the cruise control system would then reduce the amount of throttle and maintain the set speed. Additionally, cruise control systems are deactivated as soon as the brake is applied. As braking is usually an automatic reaction in most emergency situations, the scenario of cruise control causing an increase in vehicle speed is highly unlikely.” Maybe it is ok in the southern hemisphere, but a problem north of the equator.