Using Cruise Control in Rain
Sep 29, 2006 | 07:45 PM
#1
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From: Southlake/Lubbock, Texas
Using Cruise Control in Rain
Got this in an email today, apparently it was verified on snopes. Whatdya think? 
"A 36 year old female had an accident several weeks
ago and totaled her car.
A resident of Kilgore, Texas, she was traveling
between Gladewater & Kilgore. It was raining, though
not excessively, 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 hydroplane --
when your tires lose 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.
The highway patrol estimated her car was actually
traveling through the air at 10 to 15mls per hour
faster than the speed set on the cruise control.
The patrolman said this warning should be listed,
on the driver's 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, totaled his car and sustained
severe injuries."
ago and totaled her car.
A resident of Kilgore, Texas, she was traveling
between Gladewater & Kilgore. It was raining, though
not excessively, 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 hydroplane --
when your tires lose 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.
The highway patrol estimated her car was actually
traveling through the air at 10 to 15mls per hour
faster than the speed set on the cruise control.
The patrolman said this warning should be listed,
on the driver's 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, totaled his car and sustained
severe injuries."
Sep 29, 2006 | 07:50 PM
#2
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hmm, I never use cruise anyways in bad weather, you need to be prepared for anything that may happen, plus Toyota's cruise control floors it if you get 1mph off, so I really don't use it that often anyways even with the roads dry
Sep 29, 2006 | 07:53 PM
#3
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From: Southlake/Lubbock, Texas
Im not sure I buy the bit about "taking off in the air." Seems like it would spin out 100x before whatever freak combination of physics occured such that it became airborne.
Sep 29, 2006 | 07:56 PM
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I agree thats a little far out, but I was just thinking, lets say she had it on a steep incline, with maybe a small dip in the road with standing water, the CC floors the gas, hydroplanes at the top of the hill, and jumps the hill? Mabye far out, but not altogether impossible, I think??
Sep 29, 2006 | 07:56 PM
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From: Southlake/Lubbock, Texas
Sep 29, 2006 | 08:04 PM
#7
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From: Southlake/Lubbock, Texas
I agree thats a little far out, but I was just thinking, lets say she had it on a steep incline, with maybe a small dip in the road with standing water, the CC floors the gas, hydroplanes at the top of the hill, and jumps the hill? Mabye far out, but not altogether impossible, I think??
Im curious if the location of the CC speed sensor matters. If speed is measured at the driving axle, it seems that the CC would sense an increased speed as traction decreased and would cut throttle- not apply more throttle. Same as when you are going down a hill with CC on and it cuts the throttle a little to maintain the set speed.
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Sep 30, 2006 | 11:45 AM
#10
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From: Glenville, NY
This whole story sounds 'fishy' to me. Not that I think using CC on bad road conditions is a good idea, but I can't see how a vehicle could just 'jump' into the air because of the CC.
I have seen several DOT videos of how hydroplaning affects a vehicles wheels, and it depends on which wheel looses traction as to how it reacts.
If you are in 2wd/rwd and a front tire starts to hydroplane, it stops rotating because it has lost contact with the road and that contact is what keeps it turning. It will not start turning until the vehicle speed drops low enough for the tire to 'drop' through the layer of water and again contact the pavement. In most cases, the front wheel will hydroplane before the rear because the rear is tracking in the path of the front which has already broken the surface tension of the water. As for a drive wheel, it would depend on how the CC senses vehicle speed as to how it would react. Given the way the newer traction control systems work, I would think any difference in a wheels rotation from the rest would activate traction control and that would cancel CC operation.
This particular story, IMHO, has all the markings of an urban myth.
I have seen several DOT videos of how hydroplaning affects a vehicles wheels, and it depends on which wheel looses traction as to how it reacts.
If you are in 2wd/rwd and a front tire starts to hydroplane, it stops rotating because it has lost contact with the road and that contact is what keeps it turning. It will not start turning until the vehicle speed drops low enough for the tire to 'drop' through the layer of water and again contact the pavement. In most cases, the front wheel will hydroplane before the rear because the rear is tracking in the path of the front which has already broken the surface tension of the water. As for a drive wheel, it would depend on how the CC senses vehicle speed as to how it would react. Given the way the newer traction control systems work, I would think any difference in a wheels rotation from the rest would activate traction control and that would cancel CC operation.
This particular story, IMHO, has all the markings of an urban myth.
Jan 23, 2007 | 05:09 PM
#12
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From: Newnan, GA - Stillwater, OK
I can vouch for the system flooring it once the speed drops.
Jan 30, 2007 | 11:39 PM
#14
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From: Cal Poly Pomona or Redlands, CA
ok so i have a question. if your cc is on, and your tires loose traction, wouldnt they start spinning faster as they are no longer fighting the air resistance and friction of pushing the weight of the vehicle but at that instance, the rpm has not changed. sensing the increase of wheel speed, wouldnt the cc throttle back the engine? this is assuming wheel speed is measured from the drive shaft, transmission, etc. something connected to the drive wheels, and not a speed sensor. someone please correct me on this and explain why cc would cause you to go out of control.
now im not saying ya or nay to this. i rarely ever use my cruise control, as all i drive is the 10 east and west between redlands and pomona, and speeds range from 110 to 0, and speeds drop faster than hooker's panties.
now im not saying ya or nay to this. i rarely ever use my cruise control, as all i drive is the 10 east and west between redlands and pomona, and speeds range from 110 to 0, and speeds drop faster than hooker's panties.
Last edited by seanz0rz; Jan 30, 2007 at 11:41 PM.
Jan 31, 2007 | 03:30 AM
#15
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From: Tulsa, OK
I had four main thoughts on this article...
1. The car cannot accelerate if the drive wheels are hydroplaning - if hydroplaning, the tires have no friction against the road wherewith to propel the car.
2. The original story was written about a Lincoln Town Car (according to Snopes) which would be 2x4, RWD.
3. As TechWrench explained, the front wheels will hydroplane first, thus you lose almost all braking functionality (or all of it if your rear brakes don't engage properly) but your rear wheels could still be making contact with the pavement. Thus, you could be powering the car along with no steering or braking.
4. If it was one of Ford's Better Ideas to measure the CC speed at either front axle, then the CC would accelerate the car since the front wheel RPM drops when it hydroplanes.
1. The car cannot accelerate if the drive wheels are hydroplaning - if hydroplaning, the tires have no friction against the road wherewith to propel the car.
2. The original story was written about a Lincoln Town Car (according to Snopes) which would be 2x4, RWD.
3. As TechWrench explained, the front wheels will hydroplane first, thus you lose almost all braking functionality (or all of it if your rear brakes don't engage properly) but your rear wheels could still be making contact with the pavement. Thus, you could be powering the car along with no steering or braking.
4. If it was one of Ford's Better Ideas to measure the CC speed at either front axle, then the CC would accelerate the car since the front wheel RPM drops when it hydroplanes.
Jan 31, 2007 | 04:32 AM
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From: Lat: 40° 47' 01" Long:-78° 00' 58"
CC systems typically monitor speed at the transmission. When the drive wheel(s) hydroplane, it typically causes the wheel to over accelerate, if only for a few seconds. A heavily over accelerated wheel(s) that regains contact with the pavement will propel the vehicle abruptly causing a sensation of being 'airborne'. This 'airborne' sensation is exaggerated if the driver attempted any corrective steering adjustments while hydroplaning, thus propelling the vehicle in any given direction or careen completely out of control once wheel contact is established on the already slick conditions.
In my opinion, the best thing to do when hydroplaning is let off the throttle, hold the wheel steady, not making any abrupt movements (assuming you're not navigating a severe curve), until the wheel(s) regains contact. Until then, you're basically helpless.
In my opinion, the best thing to do when hydroplaning is let off the throttle, hold the wheel steady, not making any abrupt movements (assuming you're not navigating a severe curve), until the wheel(s) regains contact. Until then, you're basically helpless.
Last edited by hillbilly; Jan 31, 2007 at 07:25 AM.
Feb 17, 2007 | 09:57 PM
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CC & Bad Weather.. Not Good.
Two weeks after hearing that story I was skeptical about the use of CC in wet weather but soon (too soon) I found out that icy conditions are bad if not worse than wet conditions. I was crossing a bridge which apparently was not noticeably icy and had my cruise on. After I realized that the rear of my '97 Runner was swinging to the left and the tach was registering about 3500 RPM I had a flashback of the hydroplaning story and disengaged the CC at the switch and not by hitting the brakes which I feel would have only worsened the loss of traction. The second I disengaged the CC I regained instant control and avoided possible disaster. Never again shall I use CC when any conditions other than dry pavement exist. Please, don't regard this story or any other similar story as a load of crap based on inexperienced, careless drivers who lack decent driving skills. I am not one of them and I have learned "first hand" of this scenario as TRUE. Remember the "ounce of prevention" rule and be safe, not sorry.
Feb 18, 2007 | 08:15 AM
#19
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From: Longmont, CO
Sorry, gonna need more proof, because using cruise control in ICY conditions leads me to believe otherwise....
