They run the car thru a pool of water, and then
put 500 HP or so to it while the front brakes are on.
The water lets the tires get spinning and soon
there is a layer of melted rubber. Which
gets the tires up to proper temperature for
More extreme than the heater I posted earlier upthread.
Nothing besides tire rubber on asphalt is going to be
I would be amazed if such a chemical can exist without being
really bad for the environment.
The first thing you have to do is understand how a tire
grabs the surface. Hint, it isn't what you learned in
Physics 101. Tire grip is due to the energy that
the tire uses to deform around the surface of the road.
Think of the road as a sandpaper surface and the tire
grabbing into the nooks and cranies.
Any goop is going to fill the nooks and cranies and
decrease traction for a while, probably longer
than the top will take.
How about a great light or flashbulb that can heat three
quaters of the tire's surface up to optimal temperature?
On icy roads, you can use sand. On clean, dry roads, tires work really
well, and any sort of grit or adhesive will become a lubricant.
In summer, you might try using a jet of compressed air or other gas to clean
the road ahead of the tire. This could clear away water and sand to prevent
hydroplaning and slipping.
On Sun, 20 Nov 2005 21:18:37 -0500, "Matt Timmermans"
This brings up the idea of having some continuous sensor(s)
evaluate (using methods beyond the scope of this post) the condition
of the road, and when a "stop car fast" request is made, immediately
decide what, if anything, to spray or release onto the tires or road
to aid in friction. This gets by your point 3), in that it won't make
the conditions worse, because it won't be released on inappropriate
The only way I can envision would be additional tires, or maybe a belt like
a treadmill, tucked in the undercarraige of the car that deploy to increase
the surface area of the road contact surfaces. This apparatus would then
either have to have some kind of resistance to kinetic energy (flywheel,
torsion) or a dynamic braking system too slow the vehicle.
Could be messy for the home mechanic working on his vehicle on jackstands
and it deploys while he's under there!! :-(
The thing is, friction is proportional to the normal force, not to the
contact area. All else being equal doubling the contact area does nothing.
In the real world changing the contact area in either direction may
increase, decrease, or have no effect on the frictional force depending on
the details of what is happening at the contact surface. If the braking
device used a different rubber compound optimized for stopping and not
compromised to provide long service life it might allow for somewhat
shorter stops, but I doubt that the gain would be really large.
I'm a bit puzzled as to what a flywheel or regenerative braking system would
bring to the party, though, other than more weight and complexity in a
system that is already too heavy and too complex.
Why a treadmill? why not just a big block of gumball rubber?
With a strong factor for coefficient of friction. In theory
a big hunk of gumball could have a much higher coefficient
of friction. In practice it won't, it will have lots of
road dirt, oil, water, etc thrown up on it when not in use, so it
will hurt. Plus it will add weight to the vehicle all the time,
adding mass that must be slowed down. And hurting things like
ride quality, gas mileage, etc.
either of these recover energy. They still rely on friction of tire
to road, so they can't do more than brakes can. They are just different
brakes, capturing some energy rather than throwing it all away
Thinking about this, I think you're working the wrong end of the problem.
The collision avoidance system should prevent a situation from arising such
that increasing the static friction would be needed. This means making an
ongoing assessment of the road surface and conditions and making allowances
for a disparity of braking power between the CAS-equipped vehicle and the
one ahead, as well as looking ahead of that vehicle and analyzing the
traffic pattern to assess the possibility that it will collide with an
Something that would IMO be highly beneficial would be an aft-looking
analysis as well--stopping successfully in heavy fog for example is not the
end of the game--to be safe you also need to clear the road surface
completely as otherwise you risk being hit hard by something coming from
behind (this is not an uncommon kind of collision in areas where heavy fog
is frequent), and I think it would be worthwhile for the CAS to either do
that or make a recommendation to the driver that it be done.
Now, someone may cut your CAS-equipped vehicle off and then manage somehow
to stop suddenly, but in that case there would be only a narrow range of
distances over which your increased-friction device would be of
benefit--this would be an infrequently occurring scenario if your
programming is good.
I think a more interesting problem is "edge of the road" analysis--seems to
me your system should have "hit the ditch" as an option and that requires
that it be able to assess the viability of the ditch as an escape zone.
As to how it's going to handle some idiot playing "chicken", I don't know if
anybody has every come up with a proven survival strategy for that game.
On Wed, Nov 23, 2005 at 06:45:23AM -0500, J. Clarke wrote:
Jeez, the quality of this group is really going downhill. Everyone
knows that the tunnel, once painted, only works for RoadRunner
himself. Once you (Wiley) attempt to pass, you smack into said
object. Come on - do some research and get your facts straight! :-)
Isn't that just the Acme brand paint that does once through thingie,
Come to think of it, there's probably an Acme Brake Enhancer you could
order. It too would depend on who was trying to use the brakes. ;)
Of course we should do everything reasonable to prevent an accident
in the first place. But that is not always possible. I don't think
you would argue for the elimination of seatbelts and airbags. Safety
systems need to be designed with multiple layers.
Yes, this is a very good point. If the aft-looking radar detects
a vehicle approaching too fast from the rear, it could turn on a pair
of narrow beam strobe lights bright enough to penetrate the fog/rain.
A pair is necessary to give the approaching driver enough perspective
to judge distance, and a pulsing strobe grabs attention better.
If that fails, then I think your suggestion of pulling off the road
completely is a good idea. That will require the computer to monitor
the condition of the shoulder, but that shouldn't be too difficult,
since it will already be monitoring adjacent lanes.
It's just good old Chlorox (bleach).
The dragsters used to spin out in the "bleach box" to warm their tires,
and the bleach both cleaned and softened the rubber surface. I've heard
you can use bleach to get more traction on ice as well.
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