stop car at 30mph in 100ft.

Well then there is your problem...
Get serious.
This is going to have to be done on a wrecker, a car due to be scrapped.

From one of my mates at work, whats to stop something jamming the wheel-arch.
Chuck a tyre, or something similar, under the back of the wheel, let it rotate into the wheel-arch and jam the wheel.
Sure the wheel will lock, but a skid to stop in 30 yds or so is better than a brick wall at 99 yds?...

I know that one, its being put into tests somewhere in UK, where its set to replace the spike strip, because the thing will stop a TRUCK, and those with run-flats as well.

How about blowing out the suspension, making the body of the car fall down onto the wheels and stopping the car by the sheer weight on the tires preventing them from rolling?

Place small shape charges on two points of both the springs and the shock absorbers, top and bottom, and put an emergency detonator button in the car. If both the regular brake and the e-brake are taken out, push the button and the shape charges blow the springs and shock absorbers clean out.

Could that work?

Hit the tree at 30, or steer round into the next one at 20...

Brake fade is not nice, I have experienced it, it kind of makes your stomach upset.

The idea of strong mats anchored to the car is good.
The idea of an "escaper lane" has been used, unfortunately, its not always that portable?...
Suspension collapse, if you had an air-ride system, dumping the air would work I suppose?...

I think I like the idea.

Construction of the mat?
You couldn't just pull the mat out from under your feet, so, what to use, treaded or untreaded, can you use something like a cut tyre, how to store it, how to deploy it?....

Dropping the suspension is a really bad idea. The underside is going to scrape on the ground, which apart from tearing the road up is likely to rip the fuel tank open.

Remember that cops get somewhat concerned when people try driving on rims because the sparks can set fire to the car and fuel tank.

Oh, and you loose all measure of control over the car by dropping it on the body.

The net seen above is basically the emergency barrier system used on aircraft carriers since the first world war. Another system that you could theoretically take from carriers and use on cars is the arrester wire. A retractable hook system would be easy enough to put on a car under the rear part of the frame, and wouldn't have to be activated by hydraulics.
The catch is that you'd have to heavily reinforce the frame to prevent the hook or frame from detaching from the rest of the car - which IS possible as there are carrier aircraft far heavier than anything but the largest ground vehicles and they have landing speeds higher than most cars will usually be traveling.
Of course the deceleration would probably wreck the car anyway, and would certainly set off the airbags (which might not be a bad idea all things considered). But it would be preferable to hitting a tree.

Come to think of it as an emergency stopping system the arrester-wire would be kind of neat to see in a car, even if it wouldn't exactly be practical 99.99% of the time.

What is needed here is a myth/story about an unusual way someone managed to bring a car to a stop, or a car being stopped in an unusual way safely. (The higher the speed the better)

Have they done stopping one car with another? Or did I imagine that?

Anyway. These are kind of interesting things to think about, and I could see them having some fun coming up with ideas and designs. But they need a 'real' myth to start from.

I might have found us something.

This video tells you that in an emergency where your brakes fail, you should NOT pump your brakes:



Meanwhile, this site: www.wikihow.com/Stop-a-Car-with-No-Brakes tells you that's exactly what you SHOULD do, because it may rebuild enough pressure in the braking system for you to stop.

A third site I've found (www.driversedguru.com/driving-articles/car-auto-emergencies/brake-failure-steering-failure/) seems to agree a little bit with both, depending on whether you have ABS or not. It says that with ABS, you should simply press hard on the pedal and hold it and the ABS should kick in. Without ABS, pumping is needed to build up pressure.

I personally know that the last site is right, but I have 5 different driver's licenses, so I should know. But does the average driver? After looking through a myriad of online auto forums, I'd say no. The discussion about pump vs. don't pump if your brakes fail rages on, so it would seem there are a lot of misconceptions out there about this question.

Giving a definitive answer to that question might lead to the "ramp it up" section about what you could do in the unlikely scenario that both your main brakes and your E-brakes fail at the same time, leading to some of your ideas being tested.

the video - first, is skimpy on details, and second, is about a throttle jam rather than a brake failure.

as for brake failures themselves, there are multiple reasons for brake failure. if you have broken brake lines, then there is no good recovery - you're left with the E-brake. if you are low on fluid, or have overheated fluid, pumping can help increase hydraulic pressure if the brakes are overheated, then you're pretty much needing lots of room for a run-down, or a runaway ramp.
if your brake booster has gone bonkers and is fighting you instead of helping you - you also need a lot of room, or the e-brake.