How Powerful the Brakes Really are...

While getting my haircut this afternoon, i had the opportunity to read the latest (March) issue of Car & Driver. They did some experiments on the 2010 (or 2009) Camry that I already know, but many folks here still don't get, or realize.

They ran the Camry up to 60 mph and then simultaneously floored the gas (to simulate an open, runaway acceleration conditions). At the same time they slammed on the brakes while keeping the gas peddle to the floor. Their findings:

- The 60-0 stopping distance under this condition was 16 feet longer than the stopping distance without the gas peddle floored.

BUT EVEN WITH THE GAS PEDDLE TO THE FLOOR....

- The 60-0 stopping distance for the floored Camry was 1 foot shorter than the Ford Taurus. Yikes!!


As I've said several times before - There is no engine made on a production vehicle that can over-power the brakes on a car. None. If you find yourself in such a situation, just hammer the brakes....you will come to a stop.

 

LOL. Sorry, but it is. Try doing some reading on this, and you will find out that pretty much all car experts agree. been to 3 different driving schools, and that's one of the first things they tell you - "trust and use your brakes, they are the most powerful system on the car". Fact, they are. Are there exceptions? Sure, there are exceptions to everything. It's just not probable.

Of course it goes without saying that the brakes have to be in good working operation, and not dangerously worn brake pad, or rotors. Did you even read the CR report? CR's test was flawed. The biggest problem with their test proceedure was - "We then drove a lap around our test course to cool the brakes and repeated the procedure." This is just idiotic. The brake pads are not going to cool down to the point they won't fade with just one lap. Had they done the experiment at 60 mph - from the start - and then tried to stop the vehicle, it would have stopped. The pads had already been compromised when they did their 2nd tests. CR should really stick to evaluating toaster ovens, and leave car evaluations to those that do it for a living.

All this said, this experiement has already been done on a Prius: http://priuschat.com/forums/gen-iii...9-toyota-suspends-sales-recalled-vehicle.html

"Our '06 Prius must have a "smart throttle".

"Recently, I went out on the free way and at 60 mph floored the throttle and pushed on the brake pedal at the same time. The acceleration was immediately cut and the car began to slow dramatically to a stop. When I released the brake the accelreation returned untill I again applied the brake. The brake application with this car cuts acceleration immediately.


I've done this test on several different vehicles, with much higher HP than any of these cars, and it works. End of story.

Oh, I'm NOT advocating that if this happens to you, that this is your ONLY option. Certainly holding in the PWR button for 3 seconds (if you have the forthsight to remember to hold it for 3 seconds to turn the car off) is a viable option. Putting it in neutral is another. Whatever works for you. Both most people's knee-jerk reaction to a car rapidly accelerating is to hit the brakes. First reaction most of us have.

But to be clear - To those owners who said they could NOT even slow the car down by pressing on the brakes, I say they either have a defective brake OR, they weren't pressing the brake peddle at all. But it's highly unlikely that two systems - acceleration control and braking - would both fail at the same time.

 

How To Deal With Unintended Acceleration - Tech Dept. - Auto Reviews - Car and Driver


CAR & DRIVER:

"Our tests were conducted at highway speeds, as the incident with the Lexus ES350 happened on an expressway, and in the lowest possible gear, as that's the worst-case scenario. Here is how to deal with a runaway car:

Hit the Brakes

Certainly the most natural reaction to a stuck-throttle emergency is to stomp on the brake pedal, possibly with both feet. And despite dramatic horsepower increases since C/D’s 1987 unintended-acceleration test of an Audi 5000, brakes by and large can still overpower and rein in an engine roaring under full throttle. With the Camry’s throttle pinned while going 70 mph, the brakes easily overcame all 268 horsepower straining against them and stopped the car in 190 feet—that’s a foot shorter than the performance of a Ford Taurus without any gas-pedal problems and just 16 feet longer than with the Camry’s throttle closed. From 100 mph, the stopping-distance differential was 88 feet—noticeable to be sure, but the car still slowed enthusiastically enough to impart a feeling of confidence. We also tried one go-for-broke run at 120 mph, and, even then, the car quickly decelerated to about 10 mph before the brakes got excessively hot and the car refused to decelerate any further. So even in the most extreme case, it should be possible to get a car’s speed down to a point where a resulting accident should be a low-speed and relatively minor event."

 

Do you know what "brake fading" is? That's what I am talking about.

 

You sir, are insulting by saying that I "am wrong". I am not wrong. Neither is C&D. Neither is Road and track. Neither is Motor Trend. Neither are the professional drivers who teach this stuff for a living. Neither is the Prius owner who tested and reported this on this prius web site. The test is flawed. Get a better understanding how the brakes work before you say "I am wrong".

Please read my last two paragraph. I stand 100% by this. Period.

Baloney. How would anyone know they were on fire or red hot? Somebody next to them reported red hot brake pads? Please. The car careened off the road and subsequently burst into flames. The car was an inferno. That aside, the Lexus owner in the 911 call said, and I quote, "I have no brakes". Sounds to me he had complete brake failure. Maybe he had no/little brake fluid?

I've read no report that said the brakes were "on fire" due to the owner trying to stop the Lexus. Please provide your proof? The car went off the road and burst into flames, and the car was destroyed. If there was evidence that the brakes were charded/melted, etc, it's probably because the car was an inferno. Did you read the report?

Here are a few excerpts from the report:

"SANTEE, CALIFORNIA—A horrific sudden unintended acceleration crash that killed four – including a California Highway Patrol officer who was at the wheel of the 2009 Lexus when it plunged over an embankment and burst into flames – may raise the profile of SUA incidents as the National Highway Traffic Safety Administration weighs granting a defect petition to re-investigate the problem in Lexus vehicles.


The tape of the brief call, released to the public last week, features the voice of Lastrella, telling the operator that the vehicle had no brakes.

The Lexus ES350 is a case in point. In October 2007, NHTSA closed an Engineering Analysis into unintended acceleration, affecting 55,000 2002- 2008 Lexus ES350 and Toyota Camry vehicles. Drivers had reported that vehicles continued travelling full throttle despite attempts to stop the vehicle. Some reacted by applying the brake pedal multiple times, depleting the braking system’s vacuum-based power assist and overheating the brakes, which further diminished the brakes’ effectiveness. Others attempted to turn the vehicle off by depressing the engine control button, unaware that the button had to be depressed for three seconds to stop the engine when the vehicle is in motion."

The owner of the lexus reports, in the 911 transcript, that the car "had no brakes". Gee, I could be wrong, but if the car has "no brakes", stepping on the brakes will not bring the car to a stop.


Furthermore, from From CR: http://www.consumerreports.org/cro/...s/cr_suddenunintended-acceleration_012910.pdf

Please note the first thing CR recommends. Please note (in #1) the warning NOT to turn the car off at that point....and the 2nd paragraph (above) as it relates to braking system's vacuum assist. Furthermore, as per the 2nd paragraph (above), one should also NOT pump the brakes. Apply steady pressure - continually.

CR's recommended steps:

(1) Firmly apply the brakes. Do not release your foot off the brakes (ie do not pump the brakes)...and do NOT turn the vehicle off at this point.

(2) Put the car in neutral

(3) steer to a safe place

(4) last step - turn the car off.


Clearly, if you are the type of driver that does not maintain his car, and lets the brake pads wear down to nothing, or never changes the brake fluid, or has bad/irregular rotors, etc...then step #1 isn't going to be very effecting...now, is it? Pressing and releasing, pressing and releasing...again and again, does more harm than good, and causes the brake pads to fade and dramatically reduces the braking effectiveness. This (should) go without saying.

So I'll say this again, as clearly as I can - If you have a car, a truck, a mini-van, and SUV where the brakes are working properly, then if you experience an unintended acceleration moment, if you firmly apply your foot to the brakes (without releasing, without pumping the brakes, and without turning off the car)...that action will bring the car to a dead stop. Period. There is no question about this. I learned, and have practiced this myself in numerous advanced driving schools. I've read numerous tests conducted by many different car magazines....and I've read testimonials from owners of prii to Corvettes. It will stop if the brakes are working properly.

 

I think people momentarily take their foot off the brake because they assume either: (1) they need to "pump" their brakes to get more fluid pressure, OR (2) they need to cool the brake pads. Either reason is wrong. Taking your foot off the brake peddle for a few seconds is not enough time to let the pads cool down. Even the CR test was flawed because they thought by driving once around a short track, that the pads would have cooled down...simply NOT the case. Brake pads retain heat for a long time.

I got slammed for making this statement a while ago (on a different thread) - but most American drivers really know little about their cars, or how to handle them in emergency situations. I really would encourage everyone to spend $500 and take a 2-3 day driving course on a track...well, well, worth the money, and may one day save your life.

 

Mmmm, well, we trust our brakes every day...even if you leave plenty of space in front of you, there's nothing to say that someone won't swerve in front of you, a kid jumps out in front of the car, etc, etc..

We're talking about an emergency situation, when all of a sudden, your Lexus takes off like it was possessed....then apply steady pressure to the brakes (duh?!), put the car in neutral, steer to a safe place (if you can), and finally, turn off the engine. If brakes have failed, or will not bring the car to a stop, then something is wrong with the brake system, and one should go to step #2 - put the car in neutral.

 

It's amazing how little attention most people pay to their brakes, and maintaining them so that they will work correctly when you need them most...