Cruise control in the rain.

RichardD1970

Just had a post on my Facebook,

Excellent Driving Tip: Especially for the young drivers!

A 36 year old female had an accident several weeks ago. 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 Police Officer what had happened, he told her something that every driver should know -

NEVER DRIVE IN THE RAIN WITH YOUR CRUISE CONTROL ON..

She thought she was being cautious by setting the cruise control and maintaining a safe consistent speed in the rain.... But the Police Officer told her that if the cruise control is on,your car will begin to hydro-plane when the tires lose contact with the road, and your car will accelerate to a higher rate of speed making you take off like an airplane. She told the Officer that was exactly what had occurred. The Officer said this warning should be listed, on the driver's seat sun-visor along with the airbag warning.

NEVER USE THE CRUISE CONTROL WHEN THE ROAD IS WET OR ICY

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 road is dry.

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

NOTE: Some vehicles (like the Toyota Sienna Limited XLE) will not allow you to set the cruise control when the windshield wipers are on.

Even if you send this to 15 people and only one of them doesn't know about it, it's still worth it. You may have saved a life.

Sounds plausible but I had never heard this before and as it was a repost by someone who could be considered a bit gullible and known to repost any and everything without checking it out I did a quick google and it appears true.

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

http://www.truthorfiction.com/rumors/c/cruisecontrol.htm#.U-MkuPldWtM

Is this common knowledge that has somehow bypassed me or not?

matttye

I wouldn't trust anything being spread around on Facebook. Even if it is true, there's so much rubbish on there.

gilbert_and_sullivan

The problem with cruise is that it gives full power to regain any speed lost, or detected, so in theory the car could wheelspin uncontrollably, but in practice ASR would cut in to prevent this happening....still not ideal.

Also, in theory, in an aquaplane situation once the car started to lose traction the wheels would speed up, but then traction control would cut the power immediately as it sensed increased speed due to wheelspin....but then once slowed it would (as they do) resume full power acceleration back to cruise speed, that alternating between power and power cut wouldn't make for ideal wet weather driving practice.

The problem is exacerbated by some drivers having not a clue whats happening at the wheels, plus as another thread is showing, running round on bald tyres they can't be bothered to look at between services...maybe the two are linked...bald tyres and lack of interest/knowledge i mean.

Shielder

I think this is a little overblown. Your cruise control will maintain a steady speed, i.e. a consistent amount of power will be applied to the driving wheels.

When you aquaplane, the wheel is moving through water too fast to efficiently move the water to the side of the wheel to maintain contact with the road surface. Hence, the wheel loses traction and you aquaplane.

You actually slow down when you aquaplane, because there is no contact between your drive and the road. It might seem like you increase speed, mainly because the engine will suddenly race, but you are slowing down.

Now, the claim in the snopes article, that you spin is correct, if you only lose traction on one side. The power through the tyre with traction will force you to one side, and if the loss of traction is not just momentary, then you can spin.

However, I've driven in rain at 70mph, with and without CC, and I'm still in one piece, and so are my cars (apart from the ones I no longer have). You drive to the road conditions, if that is 70mph (in your opinion) then drive at 70mph, with and without the CC on. Just be aware of the road conditions.

Why people insist on driving at 70mph in snow :eek: is beyond me, but that article (and my own experience with other drivers on the A9 in winter) seems to indicate that people do.

TL;DR - engage CC, but keep brain engaged too and watch the road, not your phone

Andy

photome

Not sure I believe this

Andy_L

"hydro-plane when the tires lose contact with the road, and your car will accelerate to a higher rate of speed making you take off like an airplane (sic)"

if the tires have lost contact with the road how can you accelerate?

roddydogs

Because they speed up when not in contact, then when they regaine contact the car will shoot forward.
But you knew that, didnt you?

anotheruser

roddydogs wrote: »

Because they speed up when not in contact, then when they regaine contact the car will shoot forward.
But you knew that, didnt you?

But the post doesn't state that. It suggests when the car loses contact with the road, it will speed up then, NOT when it regains contact.


It depends under what circumstances I would have thought.
If you're driving on the motorway with loads of surface water then CC is a bad idea, plus I would want to be in complete control of my speed so manual acceleration is the safest, I feel.

However if it's raining lightly and there is very little/no surface water, I'll still put CC on.

pstuart

These 'tires' sound a bit iffy to me, I'll stick with my standard tyres.

roddydogs

Some great pedants around here.

Iceweasel

Although I am trying to keep an open mind on this one - I'm struggling to believe it as it just doesn't agree with how the technology works.

Perhaps some elderly 1st generation system might - but modern Cruise Control linked to Traction Control fed info from the ABS system will not give the results described.

I think that we need to see some valid test data from MIRA perhaps as I am reluctant to believe everything I hear from Police Officers - especially traffic ones.

Edit: just checked - as I suspected it's a scare-mongering hoax started in the US of A back in 2009.

Yes - you must be careful in the wet - but this is Good 'ole US BS.