I believe it's worth revisiting US Patent 3888524 (published 1975), what with the current advances in automotive intelligence. That patent describes a winter emergency braking system which uses sand to address skidding. I suspect the idea never caught on (did it?) because when the car skids, the driver tends to freeze in horror.
I've recently had the (un)fortunate opportunity to experience the feeling first-hand -- I was driving out of a secondary alley into a boulevard, and, while trying to brake in order to check out the traffic I found my ABS clanking like crazy and the car smoothly rolling forward unhindered. I ended up instinctively pushing the brake pedal with all the force I could muster, obviously to no avail. (Thankfully there were no incoming vehicles; I went by without stopping.) On a rational level I was realizing that pushing the brake pedal that hard was useless, but I kept doing it.
Now then, I'm betting there must be a relatively simple way for the on-board computer to tell the car is skidding uncontrollably, based on the behavior of the ABS system. It should also be able to tell you're pushing the brake pedal like a madman (if you aren't the situation is probably under control -- you're skidding but there's no immediate danger). However, if you are both skidding and desperate, the computer should decide it's time to release the sand, per Patent 3888524 (you don't need to look up the patent, it's what you expect -- a sand delivery system). Of course, the sand should probably be replaced with ceramic sand or some other smart stuff, as to avoid dampening/freezing/clogging and so on -- but still, I think the basic idea makes sense.-- gutza, Jan 09 2009 I likes. Given that you seem to be skidding around your own locale lately maybe you could jerry-rig something for yourself. Hinge-mounted cans of sand on the front bumper that you can dump from inside with a string?
Then take it out on the road. Go back to that alley. See how it works.
Please link video of skid with no sand dump and with. Your photographer can wave when no cars are coming.-- bungston, Jan 09 2009 perlite as the traction enhancer.-- Sir_Misspeller, Jan 09 2009 Not sure if it still is but sand used to be put on railway tracks to improve traction.-- superjohn, Jan 09 2009 "Not sure if it still is but sand used to be put on railway tracks to improve traction."
They still do to this day. primarily I believe for traction on acceleration.-- jhomrighaus, Jan 09 2009 obscure, obtuse, rarely needed. At first i hated it, but since it would be nice if everyone else had this... I think this is one of the few situations where the car horn should be used to good effect. I have on similar occasions forced my car to pirouette on steep icy roads to slow down rather than slide into the oncoming traffic. Takes some guts to let off the brakes so the car can steer sufficiently but I was happy with the results as was the car in front of me. Passengers didn't enjoy it one bit.
Just like ABS it would be unlikely to reduce accidents as people would take greater risks and attempt more dangerous icy slopes. But i would be glad of the increased gritting.-- WcW, Jan 10 2009 @bungston, alas, I have neither the weather conditions nor the spare time to experiment, or I would -- most definitely (the snow is melting, this happened on the one day it snowed).
@superjohn, what jhomrighaus said; that's actually what got me started with this idea in the first place.
@WcW, you're right, this is rarely needed -- what's more, the people who frequently need to address this kind of weather (think Alaska) probably don't need this solution because their vehicles are well-equipped with chains and whatnot. This idea is actually targeted at the drivers/vehicles who do rarely need it -- I live in a temperate area (continental Europe -- Romania), so I would spend a couple of hundred dollars extra on this system, plus say $50 per winter for a sand reload; by contrast, for a person in Alaska it wouldn't make financial sense to invest in this because they need chains most of the time -- and chains don't involve consumables.-- gutza, Jan 10 2009 Someone I know always pumps the brake furiously when there's ice about. I keep telling them the manual says not to do that because of the ABS, but they won't listen. Perhaps that's why it doesn't do any good?-- Spacecoyote, Jan 10 2009 @Spacecoyote, the manual simply states common sense. The harder you push the brakes, the harder the wheels resist from turning. Once you exceed the friction threshold between the wheels and the road, any extra braking is utterly useless (you're adding extra resistance from turning for the wheels, but they are already not turning -- that's like trying to save energy by turning the lights off during a blackout). But then again, our brains are trained to reactions being proportional to actions, so most of us keep stepping on the brakes regardless of any rational explanation.-- gutza, Jan 10 2009 I don't think I buy it. Unless you're going very slow, or can dump a hell of a lot of sand, I don't think this will make much difference on ice.-- phoenix, Jan 10 2009 @phoenix, I'd totally love to say I tested it, but, alas, I can't. However, I think most accidents on ice proper do actually take place while going very slow -- I'm almost positive each of us know some film footage or another with two vehicles inexorably drifting towards each other at slow speed until they finally go bang.-- gutza, Jan 10 2009 not too sure about film footage... could look out my window I suppose.
I'm almost positive we've done this one before.... I remember commenting (or thinking about commenting) that trolleys use that system.-- FlyingToaster, Jan 10 2009 I've been led to believe that they use sand braking on all manner of rail vehicle.-- ye_river_xiv, Jan 10 2009 Yes. Yes. Much more practical. And it also does a small favor for those who get the 'destroyed-to- avoid eminent collision'. As it certainly was going to cause some 'body' damage to them and theirs as well. So destruction saves them that hassle.
Low tech and as luck has it low cost! A joint just a hop-skip-n-a-jump North of here has a special going on, Ammonium perchlorate 90 grain at not much more than 6 USD per kilo, bulk rate.
Practically free powdered aluminum, assorted atomized mesh.
Your HTPB or what not , well you're on you're own to find any bargains. Maybe tar.-- Sir_Misspeller, Jan 11 2009 random, halfbakery