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Cruise Control ~ Must read safety issue
Posted: Wed Mar 15, 2006 7:09 am
by Whiskey 7
Got this off a local communiqué and thought I didn't know that
Just might save your skin?
I wonder how many people know about this?
A 36-year-old female had an accident several weeks ago and totalled her car. A resident of Wollongong, NSW, she was travelling between Wollongong & Sydney. 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 tyres 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 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 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, totalled his car and sustained severe injuries.
If you send this to 15 people and only one of them doesn't know about this, then it was all worth it. You might have saved a life.
I thought of you people
Posted: Wed Mar 15, 2006 7:30 am
by werldhed
I don't mean to be an arrogant ass, but... duh.
Besides, you shouldn't have your cruise control on during adverse weather, regardless of hydroplaning. Common sense.
Posted: Wed Mar 15, 2006 7:38 am
by K-mart Shopper
I don't have cruise control. I'm saved myself!
Posted: Wed Mar 15, 2006 7:41 am
by bitWISE
werldhed wrote:I don't mean to be an arrogant ass, but... duh.
Besides, you shouldn't have your cruise control on during adverse weather, regardless of hydroplaning. Common sense.
Exactly.
I can see using it during a light rain but who the hell would use cruise control on ice or during a down-poor?
Posted: Wed Mar 15, 2006 7:58 am
by feedback
A woman?
Posted: Wed Mar 15, 2006 7:58 am
by ek
cruise control is for girls and those fake girls with dicks. oh and maybe tom cruise..
Posted: Wed Mar 15, 2006 8:26 am
by Grudge
and Sandra Bullocks, but obviously not Keanu Reeves
Posted: Wed Mar 15, 2006 8:43 am
by l0g1c
Snopes seems to say this is true.
http://www.snopes.com/autos/techno/wetroad.asp
While I will agree that cruise-control during the rain is a bad idea, I can't help but be a little skeptical of the claim that the car will, in fact, speed up when the tires are slipping.
Most cars have no idea what the ground speed of the vehicle actually is. They know the circumference of the tire and how fast they are spinning. There's no reason the car would speed up to try to gain speed relative to the ground. If she heard the engine speed up, it was most likely because of the sudden lack of resistance on the tires.
So, I believe the story up until:
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.
Anyways, just felt like picking nits.
Posted: Wed Mar 15, 2006 8:48 am
by werldhed
Why not? It's the same idea as wheels spinning faster when a car goes airborne...
It's also why they say you shouldn't spin your tires when they're not touching the ground.
Without friction or the weight of the car slowing it down, the engine is free to spin the tires as quickly as it wants. Then when you catch ground again, your wheels are spinning faster than they had been.
btw, I don't know shit about physics nor cars, so smart folks are free to call me out on this. :icon26:
Posted: Wed Mar 15, 2006 9:04 am
by l0g1c
werldhed wrote:Why not? It's the same idea as wheels spinning faster when a car goes airborne...
It's also why they say you shouldn't spin your tires when they're not touching the ground.
Without friction or the weight of the car slowing it down, the engine is free to spin the tires as quickly as it wants. Then when you catch ground again, your wheels are spinning faster than they had been.
btw, I don't know shit about physics nor cars, so smart folks are free to call me out on this. :icon26:
Ok, to make things a little clearer, let's isolate this a bit. Let's say that we had mom's minivan on a dyno and a crane hooked to the back bumper. We set the cruise at 60 and bring the van up to speed.
Now, we pull the bumper up so that the tires loose contact with the dyno. What will happen initially is that the tires will spin faster because of the sudden lack of friction, but they will not
continue to accelerate. Cruise control will see that the car's tires are spinning faster than 60 mph and ease back the throttle.
This is why I think it's impossible for a significant amount of speed to be gained (10-15 mph is what the article claims) by this phenomena.
So, yeah, sorry to gay up the thread.
Posted: Wed Mar 15, 2006 1:04 pm
by losCHUNK
i agree with l0gic, how can a car gain speed under its own power on a frictionless surface ?
and if its because of the wheels spinning really fast then hitting a piece of tarmac, then that car gained 15mph almost instantly... which is a bit hmmmmm
Posted: Wed Mar 15, 2006 1:43 pm
by Jackal
I don't think that the car "gains speed" in the air. What happens is that while the car is hydroplaning the wheels spin fast due to the lack of friction. When the tires stop hydroplaning the tires hit the ground spinning faster than they should be, causing the driver to lose control of the vehicle.
Posted: Wed Mar 15, 2006 1:46 pm
by werldhed
l0g1c wrote:werldhed wrote:Why not? It's the same idea as wheels spinning faster when a car goes airborne...
It's also why they say you shouldn't spin your tires when they're not touching the ground.
Without friction or the weight of the car slowing it down, the engine is free to spin the tires as quickly as it wants. Then when you catch ground again, your wheels are spinning faster than they had been.
btw, I don't know shit about physics nor cars, so smart folks are free to call me out on this. :icon26:
Ok, to make things a little clearer, let's isolate this a bit. Let's say that we had mom's minivan on a dyno and a crane hooked to the back bumper. We set the cruise at 60 and bring the van up to speed.
Now, we pull the bumper up so that the tires loose contact with the dyno. What will happen initially is that the tires will spin faster because of the sudden lack of friction, but they will not
continue to accelerate. Cruise control will see that the car's tires are spinning faster than 60 mph and ease back the throttle.
This is why I think it's impossible for a significant amount of speed to be gained (10-15 mph is what the article claims) by this phenomena.
So, yeah, sorry to gay up the thread.
Okay, I'll grant you that 10-15 mph is probably a bit optimistic. However, cruise control doesn't actively brake the wheels to decelerate -- it just lets them coast. So I'd believe that in a short time the wheels could be spinning fairly quickly. And 10 mph isn't really that much of an increase...
I just figured her story sounded fanstastic because she didn't really understand what was going on, and thus explained it poorly.
Posted: Wed Mar 15, 2006 2:08 pm
by tnf
And that's just another chain letter.
Posted: Wed Mar 15, 2006 2:20 pm
by plained
it work good down an iccy hill ey
Posted: Wed Mar 15, 2006 8:30 pm
by Whiskey 7
Jackal wrote:I don't think that the car "gains speed" in the air. What happens is that while the car is hydroplaning the wheels spin fast due to the lack of friction. When the tires stop hydroplaning the tires hit the ground spinning faster than they should be, causing the driver to lose control of the vehicle.
Now that sounds believeable.
Nice discussion all
l0g1c I have never seen that
snopes site. Thanks.
Posted: Wed Mar 15, 2006 9:23 pm
by Kills On Site
werldhed wrote:
Okay, I'll grant you that 10-15 mph is probably a bit optimistic. However, cruise control doesn't actively brake the wheels to decelerate -- it just lets them coast. So I'd believe that in a short time the wheels could be spinning fairly quickly. And 10 mph isn't really that much of an increase...
I just figured her story sounded fanstastic because she didn't really understand what was going on, and thus explained it poorly.
Some cruise control systems will engage the brake to maintain speed, or a set distance from a car via radar.
The reason I think that it got out of control is that the cruise control on most cars is meant to be very fluid, so it wasn't going to immidiately back off the throttle and maybe downshift. A computer can act more quickly then a human, but I am fairly certain that cruise control systems are built to be more comfortable cruising, and thus nothing happens too fast.
Posted: Wed Mar 15, 2006 11:05 pm
by Guest
Well it's definitely true but I've always known this. Not sure where I came by the info but I've always known that. It's pretty obvious too if you try it that it's not safe.
Posted: Thu Mar 16, 2006 12:27 am
by Guest
If that bitch was paying attention to the road, she wouldn't have crashed, regardless if she was using the cruise control or not. If she was just pressing on the gas and suddenly lost traction on one wheel, considering she was most likely in a fwd she would've torque steered or fishtailed in a rwd...
Posted: Thu Mar 16, 2006 12:35 am
by Guest
Actualy guys this happens to you when driving without cruise control if you keep the gas pressed at certain speeds usualy over 80km/h.
Posted: Thu Mar 16, 2006 1:22 am
by FragaGeddon
Well it was probably the extra resistance on the wheels from hydroplaning that caused the car to accelerate to keep the speed the same.
Posted: Thu Mar 16, 2006 1:37 am
by R00k
I thought it was common sense not to use cruise control in less-than-ideal driving conditions anyway.
I think it's pretty obvious, knowing how vacuum-driving cruise controls work, that if you hit a slick patch the wheels will accelerate more for a good 3 seconds or so, but it will feather it down (gradually accelerate more slowly) until it's back to the speed that was set by the driver.
And any good driver knows that accelerating in the middle of a hydroplane is just about the worst thing you can do in most situations.