Random question

[nancylebov]

twistedchick has quite a lot about how to drive safely in snow and mentions that automatic transmissions aren't smart enough to handle bad road conditions.

Could they be made smart enough with current technology?

Comments

[laughing-fox.livejournal.com]

If anything, front wheel drive cars are easier to handle in bad weather than rear-wheel, and all-wheel is better than both.

However, there is no such thing as a car that is 'smart' enough to handle bad weather conditions. Even an all-wheel drive system will end up in a wreck if the driver does something stupid. That's the problem with all those SUV's, people have this ridiculous notion that they are in a 'safe' vehicle and drive like morons. And wind up upside-down in the ditch.


Driving in snow is simple.
-Slow down
-Give yourself plenty of distance between you and the next car
-Pull out slow and easy, don't jump on the gas
-Don't jump on the brakes. Better to pump them than just slam them on
-PAY ATTENTION (i.e., no cell phones) Both hands on the wheel, and be aware of what's going on around you. Amazing how well that works ;)

[twistedchick]

All-wheel drive takes a different driving style than 2-wheel drive, and doesn't go up to highway speed easily. It's is good about 90% of the time in snow -- as in, not as good when you have to turn acute corners on a slippery road, when it turns into all-wheel sideways instead of all-wheel forward. This can be allowed for, with practice, but is a bit surprising the first time out.

In winter I still wish I had one of two past cars: the '66 Impala that had enough muscle to get through drifts, or the '79 Chevette that weighed so little it floated over them.

[laughing-fox.livejournal.com]

I haven't changed my driving style between 2, 4 and all-wheel drive. (have had cars with each). Only time I had a problem with sliding in a corner was when I foolishly went too fast into it :) But then, I grew up in the more mountainous, northern part of PA where there's snow from Oct. thru April, so perhaps I learned to drive differently?

I have to say, my best snow car was a beat up 87 subaru wagon, with on-the-fly four wheel drive. (just push a button). Low horsepower, thin wheels, and it could cut thru any amount of snow you threw at it. I even parked on *top* of snowbanks! (and if you've ever had to park in Manayunk in winter, you'd understand why I did *grinz*)

[cellio]

- Don't brake if you can down-shift.
- Maintain a steady speed; acceleration and braking cause most of the problems.

[twistedchick]

No transmission, standard or automatic, is *smart*. It's the driver who has to be smart. Automatics notice the number of revolutions the engine makes per minute and shifts to whatever is easiest (unless you do gas pedal tricks to hold it at one level or another.) They don't care what's going on outside the engine, under the wheels or on the windshield. They only respond to the gas pedal; the brakes act on the wheels, not the engine.

[madfilkentist]

That suggests a behavior of an automatic transmission which a "smart" one might be able to defeat. If the wheels lose traction, the engine will speed up, and the transmission might upshift in response, which could result in further loss of control. A smart transmission might filter out abrupt jumps in engine speed.

I've never owned a car with a true automatic transmission, so I could be all wrong on this.

[twistedchick]

Upshifting gives you more speed and less control --that's not what you want when you lose traction.

[metahacker.livejournal.com]

Yes.

Many modern cars *are* smart enough to handle snowy conditions. Unfortunately they tend to be things like the Porsche 911 -- out of the reach of the average consumer. (That particular car was so good in the snow that the reviewers ended up turning off the electronic nanny to 'have some fun'.) IIRC the high-end Forester also has the option. It is much easier to implement in a 4-wheel drive car, of course, because you've already bought some of the necessary components -- for example, center differentials that can put power into a particular wheel that has grip, or anti-lock brakes that can subtly brake an inside wheel to help you turn into a slippery corner.

At the high end, World Rally cars are *insanely* smart, with computers controlling power to each wheel individually based on a host of things including steering wheel position, throttle position, amount of 'bounce' in each wheel, inertial sensors, and a guess at the type of road surface the driver is on.

Look for things like "ESC" (electronic stability control) and "throttle by wire" (which means a computer is controlling your speed, taking occasional input from your gas pedal position, and can therefore modulate power when the wheels start to slip).

BTW, these all help during the 'accelerating' part of your drive, which can also include corners (since when you accelerate in a turn, your front tires are being asked to handle both steering and accelerating, which makes them more liable to use up all available traction and slip). ABS is still your best protection when braking. Turning is largely a matter of picking the right line and the right speed when you enter the corner.

[laughing-fox.livejournal.com]

ah, rally cars! I'm a huge rally fan :) And still cranky that they stopped showing WRC coverage here in the states...

They really are impressive, but even so, it's the skill of the driver that lets them go at such insane speeds through all conditions. And even then they still wreck them (spectacularly!) There are no mechanical or electronic fixes for someone going too hot into a tight corner on a snowy road. They can mitagate the effects, but if you push it too far you will turf it :)

[metahacker.livejournal.com]

Surely. We don't have cars that are smart enough to overcome the stupidity of their owners, yet. (In some cases, I suspect this would involve cars that refuse to leave the driveway.) But there are systems that aid...which was my point.

And...I suspect you can find WRC video coverage online, if you look hard enough. Finding it in English might be harder. ;)

[laughing-fox.livejournal.com]

heehee - I can just hear the car in the driveway, talking like HAL from 2001 A Space Odyssey..."I'm sorry Dave, I'm afraid I can't do that..."

We've been bit-torrenting WRC coverage from the UK, but it's a bit of a pain with having to convert it to a US video format. Do-able, just takes a while.