Date:         Fri, 14 Feb 2003 12:27:14 -0500
Reply-To:     SStones <sstones@IDIRECT.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         SStones <sstones@IDIRECT.COM>
Subject:      Re: Fwd: Raining-no cruise control
In-Reply-To:  <5.2.0.9.0.20030214104918.0278c3c0@pop.ipa.net>
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At 10:52 AM 2/14/03 -0600, Max wrote:
     She learned a lesson I'd like to pass on to you. You may know this
>>already--but the highway patrolman told her that you should NEVER
>>drive in the rain with your cruise control on. He said if you did and
>>hydroplaned (which she did) that when your tires were off the road
>>your car would accelerate to a high rate of speed (which it did). You
>>don't have much, if any control when you hydroplane, but you are totally
>>in
>>the hands of God when the car accelerates. She took off like she was in
>>an

Max, I'm not writing this to put you down for sharing that story, but it is
horribly exaggerated.
When the car hydroplanes (We'll say with at least one drive wheel) yes, the
engine speed and the speed of the hydroplaning drive-wheel will increase
until accounted for, either by the driver backing off of the throttle, or
the cruise control unit backing off of the throttle. The cruise control is
monitoring the car's (Or the engine's) speed. The car won't gain speed
while hydro-planing, the drive wheel is not in contact with the pavement,
unless it is being pushed by another vehicle, it will slow down slightly.
Now it would, I suppose, be possible for this woman to be driving along at
say 50 MPH. She's holding the gas pedal at about 50%, maintaining the speed
nicely...  The car hits a puddle and hydroplanes. She doesn't care that the
engine speed and actual speed of the drive wheels is up to the moon, she
sets the cruise control because the body of the car is doing the speed she
likes...  Then when the tires get back to grippable pavement, the cruise
control will try to bring the vehicle back up to the speed that the tires
were doing when spinning, but I figure that if she was hydroplaning, she'd
have better things to do with her hands than fiddle with the cruise
control. Any touch of clutch or brake should disengage the cruise control
on any factory or aftermarket unit I've heard of. I expect that most people
who drive standards would stomp the clutch immediately upon the weird
spongy feel of hydroplaning, it's just a gut reaction. Theres just no way
that the cruise control would decide to just kill you because a wheel was
able to spin freely.