Never Use The Cruise Control When The Pavement Is Wet Or Icy
02-12-07, 10:28 AM
#16
Zombie Slayer
This urban legend (and email) has been floating around for years. Your car will not suddenly fly through the air if you hydroplane with the CC on. That's a load of BS.
The reason you shouldn't use CC on wet or icy roads is because you're not in full control of your car, and the reaction time to hit the brake (or clutch pedal) and disengage CC is much slower than if you were modulating the speed with the gas pedal all along. You begin hydroplaning, and you need to get off the gas quickly to slow the vehicle's speed as fast a possible.
The person that started the hydroplane email probably did get into an accident when she was using the CC in the rain, and lost control of her car while hydroplaning, but mis-interpreted what actually happened. Your car will not take off like a airplane.
The reason you shouldn't use CC on wet or icy roads is because you're not in full control of your car, and the reaction time to hit the brake (or clutch pedal) and disengage CC is much slower than if you were modulating the speed with the gas pedal all along. You begin hydroplaning, and you need to get off the gas quickly to slow the vehicle's speed as fast a possible.
The person that started the hydroplane email probably did get into an accident when she was using the CC in the rain, and lost control of her car while hydroplaning, but mis-interpreted what actually happened. Your car will not take off like a airplane.
I'm with ff and Incendiary on this one!!!
Based on chain e-mails, I should be dead, won a billion dollars, got free Microsoft goods, lost a billion dollars, and saved roughly 145,675 people from life threatening diseases and injuries. Sooooooo, I'm going out on a limb here and say the e-mail may be less than 100% accurate.
02-12-07, 10:28 AM
#17
Your car will not accelerate when on cruise control at a constant speed - whether you run into a puddle or not. Your cruise is seeking to maintain wheel speed and will not by itself suddenly launch you into the shrubbery, but actually attempt to keep the vehicle moving at a constant pace. If drag causes the car to slow, the cruise control may kick in to return wheel speed to its setpoint.
As others have said though, it's not a good idea to use your cruise control on a slick road of any kind. YOU are in charge of the vehicle and should lift and slow gently to a controllable speed if you get into a slick patch.
As others have said though, it's not a good idea to use your cruise control on a slick road of any kind. YOU are in charge of the vehicle and should lift and slow gently to a controllable speed if you get into a slick patch.
Acceleration != Speed
Acceleration is length/(time^2)
Speed is length/time
Cruise control will try to maintain the speed you set it at. If the car say hits an upward climb, the throttle will open and accelerate the car to maintain speed. I take back what I said earlier, if cruise control works on the idea that the wheels must maintain the correct "speed" set at (not the vehicle's speed), than the car would probably lift off the throttle more likely in a situation, if it is hydroplaning. The wheels will spin more, if the car is hydroplaning; (less traction) therefore the car's wheel "speed" will increase (cruise control set speed != wheel's "speed"), the cruise control will attempt to slow down the wheels (throttle will decrease). This is all on an assumption that the vehicle determines speed of the vehicle at the wheels rather than the speed of the vehicle itself (which I believe is the case because I know the speedometer is altered if you change the wheel size of your car).
In the case of hydroplaning, you should always lift off the throttle (unless you have it floored, than lift off the throttle gently). Hitting the brakes will most likely cause you to swerve because you're still riding on water so the tires can't grip to the pavement. Even if your wheels are stopped that doesn't mean the tires grip the pavement to stop the vehicle.
02-12-07, 06:53 PM
#18
Lexus Fanatic
GS3TEK and the patrolman are both correct that cruise control should not be used in slippery conditions, but not for the reasons described in the article. The main reason that you don't want cruise on when the road is wet or slippery is that if you need to react and slow down quickly, the cruise control will add precious feet to your stopping or slowing distance, not to mention the lack of traction on the slippery road surface itself. When you have your foot on the gas maintaining speed, and lift it quickly to hit the brake, the engine RPM's cut back, the flow of gas to the engine is reduced, the drag of the decelerating transmission comes into play.....all helping to slow you down. That doesn't happen with the cruise on until you actually hit the brake, which, if the deactivation switch is working correctly, automatically disengages the unit and THEN starts the car slowing down. Then, of course, other questions come into play, like whether or not you have ABS and if the wheels will lock up.
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