This is interesting.

[1 Bravo 6]

Read this, this could save your life!!!!

A 36 year old female had an accident several weeks ago and totalled her car. A resident of Kilgore, Texas, she was travelling between Gladewater & Kilgore. It was raining, though not excessive, when her car suddenly began to hydroplane and literally flew through the air. She was not seriously injured but very stunned at the sudden occurrence!

When she explained to the highway patrolman what had happened he told her something that every driver should know -NEVER DRIVE IN THE RAIN WITH YOUR CRUISE CONTROL ON. She had thought she was being cautious by setting the cruise control and maintaining a safe consistent speed in the rain.

But the highway patrolman told her that if the cruise control is on and your car begins to hydroplaned -- when your tires loose contact with the pavement your car will accelerate to a higher rate of speed and you take off like an airplane. She told the patrolman that was exactly what had occurred. We all know you have little or no control over a car when it begins to hydroplane. You are at the mercy of the Good Lord. The highway patrol estimated her car was actually travelling through the air at 10 to 15 miles per hour faster than the speed set on the cruise control.

The patrolman said this warning should be listed, on the drivers seat sun-visor - NEVER USE THE CRUISE CONTROL WHEN THE PAVEMENT 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 pavement is dry.

The only person the accident victim found, who knew this (besides the patrolman), was a man who had had a similar accident, totalled his car and sustained severe injuries.

I must admit, it never even occurred to me.

Rick.

[EScanlon]

Although this has the flavor of an Urban Legend it is a true story. Granted the specific woman and the specific man are probably unidentifiable, but the truth of the story is correct.

If you have doubts, it's because you've never had a car hydroplane on you. If you have had a car hydroplane on you, then you know that the sudden lurch of the tires breaking loose and then starting to spin faster (for the rears) or being able to feel the front wheels suddenly go directionless.

Most cruise controls work either by determining the rate of vacuum draw from the engine and clamping the accelerator rod at that point, or they have a sensor that determines a given rotational speed and maintains it.

From what I know, the first type is the one specifically addressed by this warning. The second type, again from what I've read and heard is not affected by it.

For those of you who may wonder why this happens:

When you're traveling at a given speed, there is a set amount of resistance to the car's maintaining that speed. That resistance is what the motor has to meet in order to maintain that speed. Water under the tires allows them to spin freely, and now without the resistance of the road to them, the motor in trying to maintain the same amount of vacuum to the intake gives the engine more gas.

FWIW

[26th-Z]

The operating manual for my BMW says to not use the cruise control in wet and slippery conditions. For what it's worth.

[MikeW]

Originally posted by 1 Bravo 6

It was raining, though not excessive, when her car suddenly began to hydroplane and literally flew through the air.

[snipped]

The highway patrol estimated her car was actually travelling through the air at 10 to 15 miles per hour faster than the speed set on the cruise control.

Read the above two sentences and tell me you believe this is possible. The only way to become airborne and be going faster than you were on the road is if you hydroplaned off the side of a cliff.

The real problem here is that you lose some reaction time when it starts hydroplaning because your foot is not on the gas pedal and you don't realize as soon. The extra time required to disengage the cruise control can be critical. The following has the best explanation of the situation:

http://www.snopes.com/autos/techno/wetroad.asp

[baddriver]

I don't know about wet roads, but the guy two cubes down from me wrecked the company truck last year. It was icy and he was using the cruise control. The truck was in 2-wheel drive. Hit a patch of Ice and was in the ditch before he knew it. He didn't claim that the truck became airborn or accelerated, but the wheels broke loose and it was over.

Wet roads can sometimes be very slick, and a truck usually has a lot of power and very little weight in the back. In 4wheel-drive he probalby would have been fine.

If a car wrecked in this manner, I'd suspect someone needed some new tires.