Brake Assist - Panic Stop (Tire Pressure)

[00Sebby]

It doesn't guess. It measures your speed of actuation of the brake pedal. Try it sometime: Push the brake hard but at normal speed and the vehicle will act just like you envision. Push the brake super quick, like in a panic stop, and not even hard, and brake assist will engage. It took me exactly once before I changed my braking habits.

You are correct describing the operation and I have tested it. In normal conditions it works as I expect. I know it doesn't "guess" since it is not a living thing. But the algorithm is calculating based on the speed of my transition from gas to brake that I am in a panic situation when I'm not. For example, I see a dog running toward the road and my reaction is to quickly be ready with the brakes, maybe scrub a bit of speed, or possibly only alert a driver behind me with a brake tap that I may be slowing down. But instead, stupid computer thinks I need to lock 'er down scaring the crap out of that dog, my passengers and that driver behind me.

My problem with it is that I like driving and am an auto enthusiast, having owned in the neighborhood of 35 cars, suvs, sports cars, muscle cars, etc. I too am an engineer since the '80s most of that in the automotive industry. And I have done the whole autocross, track days, and drag racing thing. I test vehicles to make sure I know how they handle in emergency situations in rain, snow, dry, etc. so that I can react appropriately if needed, push them when conditions permit and know the limit at which they will bite. I'm not the oblivious driver going from point a to b or the clueless texter behind the wheel wondering what awesomeness my cellphone is going to show me next. I grew up without electronic driving aids but actually like most of them... abs, esc, traction control, etc. I know how they all work and what I should expect. Again, I think the 4R is great. I only want input=output. That's also why I like normally aspirated or supercharged vehicles over turbos (except for 911s and old Lotus Esprits). I like the linear response to throttle input.

 

[00Sebby]

It doesn't guess. It measures your speed of actuation of the brake pedal. ... Push the brake super quick, like in a panic stop, and not even hard, and brake assist will engage. It took me exactly once before I changed my braking habits.

Excuse the verbosity of the last post. You describe the exact reason I hate this feature. I don't want to stop hard if I don't push the pedal hard. I don't want to have to think about the possibility of unintended almost-lockup or change my brake habits because to me, the brake pedal isn't just about stopping. I may tap to disengage cruise control because a truck switched lanes right in front of me to do 2 mph faster than the truck in front of him. I may tap the brakes because an idiot motorcycle is coming up on me faster than I'm comfortable with or to signal a tailgater to back off. There has been several scenarios where this has kicked in unexpectedly or unnecessarily and it takes away from the enjoyment of the 4R.

 

[cjacob316]

The first time it happened to me I was going down hill, didn't need it, and didn't know it would happen so it startled me. Second time, it saved me from a wreck. Some genius decided to bail out of a turn last minute and swerved back in front of me going about a quarter of my speed on a highway. Someday, you'll be glad it was there.

 

[96r50]

Excuse the verbosity of the last post. You describe the exact reason I hate this feature. I don't want to stop hard if I don't push the pedal hard. I don't want to have to think about the possibility of unintended almost-lockup or change my brake habits because to me, the brake pedal isn't just about stopping. I may tap to disengage cruise control because a truck switched lanes right in front of me to do 2 mph faster than the truck in front of him. I may tap the brakes because an idiot motorcycle is coming up on me faster than I'm comfortable with or to signal a tailgater to back off. There has been several scenarios where this has kicked in unexpectedly or unnecessarily and it takes away from the enjoyment of the 4R.

Are you tapping it to the floor or something? I've tapped my brakes in many similar situations and never triggered the brake assist. I'm not sure how your managing to trigger it with a light tap of the brakes.

 

[Storm Runner]

Excuse the verbosity of the last post. You describe the exact reason I hate this feature. I don't want to stop hard if I don't push the pedal hard. I don't want to have to think about the possibility of unintended almost-lockup or change my brake habits because to me, the brake pedal isn't just about stopping.

While I wholeheartedly agree with this opinion, I disagree with the reasoning behind it.

I may tap to disengage cruise control because a truck switched lanes right in front of me to do 2 mph faster than the truck in front of him.

This unnecessary, because the same lever that engages cruise control can be used to disengage cruise control by pulling it towards you.

I may tap the brakes because an idiot motorcycle is coming up on me faster than I'm comfortable with or to signal a tailgater to back off.

Brake checking anybody, for any reason, is dangerous. It doesn't matter how close somebody is to the back of your truck. It doesn't affect you at all as long as you keep your eyes on the road ahead of you. On roads that allow it, move over and let them pass, because you never know, maybe they have to take a massive dump. :bolt: :toilet:

There has been several scenarios where this has kicked in unexpectedly or unnecessarily and it takes away from the enjoyment of the 4R.

I also agree with this. I've only had this feature kick in a couple of times, but each time it startled me and was embarrassing, because instead of a smooth controlled stop that I'm used to, my truck locked up and my tires roared like the hounds of hell.

 

[1engineer]

Are you tapping it to the floor or something? I've tapped my brakes in many similar situations and never triggered the brake assist. I'm not sure how your managing to trigger it with a light tap of the brakes.

"Tapping" (hitting the brakes quickly in the top 1/2" or so of travel) the brakes will not actuate the brake assist, no matter how fast you tap the brakes. You have to actually stab at the brakes quickly and beyond that first 1/2" or so. I too tap my brakes to deactivate cruise, etc with no unexpected results.

I understand people not wanting to change their braking method but the 4Runner is not going to change it's braking method either...
As I said it took me only one time before I figured it out and changed my method from care-free stabbing to a bit more careful (and slightly slower) method of braking. If you think by doing this it changes what will happen in a real emergency (dog runs out, car in front stops) they are wrong. It won't change that "panic" response at all as it is deeply ingrained in anyone who has been driving for awhile.

 

[00Sebby]

Are you tapping it to the floor or something? I've tapped my brakes in many similar situations and never triggered the brake assist. I'm not sure how your managing to trigger it with a light tap of the brakes.

No. "Tapping" would imply not "to the floor", right? As you can see from 1engineer's quote below, a light, quick brake action will indeed trigger the brake assist. I think he said, beyond the first "1/2 inch or so". 1/2 inch is not much pedal travel. It's not like I go around flooring my brakes all the time.

Push the brake super quick, like in a panic stop, and not even hard, and brake assist will engage.

This unnecessary, because the same lever that engages cruise control can be used to disengage cruise control by pulling it towards you.

Or I can just tap the brake to disengage cruise which is a much more intuitive action since the only reason to disengage is to slow down and it's easier than fumbling around for a lever. Most of the time, I just bump the pedal and it is fine. But, let's say I'm doing 80 and a truck doing 65 switches lanes right in front of me as I'm about to overtake it (common occurrence if you drive a lot of interstate). What would you do? I'm guessing hit the brakes quickly and a bit firmly. But I'm also guessing you don't want to lock it down on the interstate in that situation.

Brake checking anybody, for any reason, is dangerous. It doesn't matter how close somebody is to the back of your truck. It doesn't affect you at all as long as you keep your eyes on the road ahead of you. On roads that allow it, move over and let them pass, because you never know, maybe they have to take a massive dump. :bolt: :toilet:

It actually does matter how close someone follows because you cannot always control what happens in front of you. Having been the victim of two car-totaling rear-end collisions while sitting at traffic lights, I am always watching what is going on behind as well as in front of me. Who said "brake check"? If someone is speeding up behind you, your brake lights may be the stimulus they need to remember you are in front of them, make them look up from their phone, or put a bit of doubt in their mind that you may make a turn or something. I didn't say, "slam on the brakes to piss them off for driving with their head up their butt", though in some cases this happens because of the assist.

I also agree with this. I've only had this feature kick in a couple of times, but each time it startled me and was embarrassing, because instead of a smooth controlled stop that I'm used to, my truck locked up and my tires roared like the hounds of hell.

THAT'S IT!!!:cheer2: That is the complaint. The truck shouldn't do that. That's the whole point of this thread. We all put up with it but most of us who actually like being in control of the vehicle wish it wasn't there. It is probably a good thing 3% of the time and a pain in the a$$ the other times.

 

[00Sebby]

So that I can quit :deadhorse:, I learn the behavior of all my vehicles and adjust. If I don't like the adjustment, I move on to something else. My Miatas were a lot different than my '69 Z/28, which was a lot different than my Mini Coopers which were different than all of my Jeeps which were different from each other, and not like my Suburbans, etc. etc. I have adjusted to this feature of the 4Runner but just wish it was a bit less sensitive.:lookout::cheers:

 

[1engineer]

THAT'S IT!!!:cheer2: That is the complaint. The truck shouldn't do that. That's the whole point of this thread. We all put up with it but most of us who actually like being in control of the vehicle wish it wasn't there. It is probably a good thing 3% of the time and a pain in the a$$ the other times.

Again, I changed my braking habits slightly to accommodate this particular vehicle. I drive around 30K a year and most of it is interstate. When, on the odd occasion I drive my wife's vehicle, I have to get used to that particular brake system and it takes a few minutes.

As a fellow engineer you know what to do when there is a problem. You fix it! Unfortunately, in this case changing the 4Runner to your particular style of braking is not feasible (possible but really expensive and man what changes you would have to make) so to fix the problem you either change your habits or you get a vehicle that has the brakes you like. I have never fixed anything in my life (with machines) just by wishing it were different lol.

Edit: I posted this while you were writing your last post. They say the same thing!

 

[00Sebby]

Again, I changed my braking habits slightly to accommodate this particular vehicle. I drive around 30K a year and most of it is interstate. When, on the odd occasion I drive my wife's vehicle, I have to get used to that particular brake system and it takes a few minutes.

As a fellow engineer you know what to do when there is a problem. You fix it! Unfortunately, in this case changing the 4Runner to your particular style of braking is not feasible (possible but really expensive and man what changes you would have to make) so to fix the problem you either change your habits or you get a vehicle that has the brakes you like. I have never fixed anything in my life (with machines) just by wishing it were different lol.

Edit: I posted this while you were writing your last post. They say the same thing!

Same here. What's funny is I would classify my particular style of braking as normal to even minimalist. I don't slow down much for curves and usually try to plan and manage my way through traffic and obstacles in a very smooth manner.

My wife's '14 Ford doesn't do this and acts like every other car. My 15yr old is learning on her car. You know how new drivers aren't real smooth with braking, acceleration, steering, etc. LOL He would be a mess with this "safety" feature. He may even decide driving isn't worth it after a couple of unplanned assisted stops.

 

[2nd Chance]

My wife's '14 Ford doesn't do this and acts like every other car. My 15yr old is learning on her car. You know how new drivers aren't real smooth with braking, acceleration, steering, etc. LOL He would be a mess with this "safety" feature. He may even decide driving isn't worth it after a couple of unplanned assisted stops.

I also have a new driver and I plan to take her out on a road by my office so she know what to expect and then explain to her this is most likely the only car you will ever drive that this will happen with. I also plan to let her drive my 70 Camaro and let see how it feels to panic brake in a car without ABS.

ps the 700hp 2010 Camaro with 15" Brembo's she will never drive or I am hoping it will be a while before she asks.

 

[KingTaco]

I experienced brake assist yesterday! I was on my way home from work at the beginning of a very heavy thunderstorm. A car approaching from a sidestreet on my right did not stop at his stop sign, and began his left hand turn at a high rate of speed right in front of the car I was following. The guy making the turn did the worst thing he could've done; slammed on his brakes, and stopped dead perpendicular in the roadway (his Mercedes did stop extremely quickly in the rain). I hit the brakes hard, as did the car in front of me. The brake assist felt much different than ABS to me. The moment of "hold" felt longer than the quick, intermittent chirp I expected. I didn't feel like I had as much control as anticipated. I'm sure the slick road and AT tires contributed to this, but I don't know that the result was any better (or even as good) as if I had ABS only.

I understand what the system is doing, but even after reading through this thread, I'm still a bit confused as to why. There was a split second where I almost took my foot back off the brake because of the way it reacted. The bottom line is that I was following at a safe enough distance, and the brakes performed well enough that there was no collision. I'm happy about that, but I think ABS alone would've produced the same (or better) result. Can anyone help me understand the benefit to brake assist?

 

[philsey]

... Can anyone help me understand the benefit to brake assist?

It's not for you, nor those of us who drive attentively. It's for those who are texting, eating, putting on mascara, fiddling with the tunes, talking smack with the back seat homies, or otherwise mentally masturbating while driving.

Unfortunately, Toyota has no algorithm for detecting the above, so we all get it.

Since 2010, I've had the pleasure twice, and it saved me from worse than momentary embarrassment both times. Once my fault, and once not.

 

[catrains]

I experienced brake assist yesterday! I was on my way home from work at the beginning of a very heavy thunderstorm. A car approaching from a sidestreet on my right did not stop at his stop sign, and began his left hand turn at a high rate of speed right in front of the car I was following. The guy making the turn did the worst thing he could've done; slammed on his brakes, and stopped dead perpendicular in the roadway (his Mercedes did stop extremely quickly in the rain). I hit the brakes hard, as did the car in front of me. The brake assist felt much different than ABS to me. The moment of "hold" felt longer than the quick, intermittent chirp I expected. I didn't feel like I had as much control as anticipated. I'm sure the slick road and AT tires contributed to this, but I don't know that the result was any better (or even as good) as if I had ABS only.

I understand what the system is doing, but even after reading through this thread, I'm still a bit confused as to why. There was a split second where I almost took my foot back off the brake because of the way it reacted. The bottom line is that I was following at a safe enough distance, and the brakes performed well enough that there was no collision. I'm happy about that, but I think ABS alone would've produced the same (or better) result. Can anyone help me understand the benefit to brake assist?

I am no expert on toyota brake assist . on GM vehicles many including me have had ABS come on due to road surface being icy/wet etc and when you brake too hard the ABS will continue to activate and you will never stop at a reasonable distance it just keeps on pulsing.

another case where this occurs is when braking on a bad road surface with bumps / frost heaves .. coming off some of the hywy exit ramps when your slowly braking this surface will get the ABS to come on every time the vehicle bounces upward .

I have pulled the ABS fuse at times and found I do a much better job than the ABS feature on my GM truck.

 

[1000MPH]

.... There was a split second where I almost took my foot back off the brake because of the way it reacted. The bottom line is that I was following at a safe enough distance, and the brakes performed well enough that there was no collision. I'm happy about that, but I think ABS alone would've produced the same (or better) result. Can anyone help me understand the benefit to brake assist?

You answered your own question. The system was designed for people who are not expert drivers, who are hesitant when maximum pedal pressure should be applied.

If you guys think this system sucks I suggest going for a test drive in some of the new cars with collision avoidance systems.

 

[2nd Chance]

If you guys think this system sucks I suggest going for a test drive in some of the new cars with collision avoidance systems.

I chimed in early on this conversation and here is where I stand or sit today on it. Yes it works but I promise you it will scare the crap out of you the first couple times you use it especially in the rain. Every now and then I slam on the brakes just so I can actually get used to it. I have even told my wife to take the truck out and do a couple panic stops so she doesn't soil herself when she is actually in a panic situation.

There was a split second where I almost took my foot back off the brake because of the way it reacted.

I actually took my foot off the brake and then reapplied the brake jsut like I do in my 70 Camaro. Which btw stop as good or better then the 4Runner.

 

[007Tacoma]

So, is Brake Assist different on different 4Runners?

My 2003 SE 4WD never did this?

My 2015 TEP did it once where there really was a panic situation and saved my life. In the past 51,000 miles of driving my 2015 over the past year, that has only happened once.

Here is the video:
https://youtu.be/sWxhgxHV8to

<iframe width="560" height="315" src="https://www.youtube.com/embed/sWxhgxHV8to" frameborder="0" allowfullscreen></iframe>

 

[pcrdude]

This is how it's supposed to work.

https://youtu.be/NwlEslInxyE

Maybe the rear weight sensors in the OPs rig are sending bad info to the ECU?

 

[JerseyMike]

Brake checking anybody, for any reason, is dangerous. It doesn't matter how close somebody is to the back of your truck. It doesn't affect you at all as long as you keep your eyes on the road ahead of you. On roads that allow it, move over and let them pass, because you never know, maybe they have to take a massive dump. :bolt: :toilet:

Not to mention if you get nabbed riding right in some states it's not only a $300 failure to yield ticket, but another $50 surcharge, and 2 points. The good old "brake check" can get you slapped with a reckless driving charge - max 3 months in jail, mandatory $500 fine, 5 points. Plus the risk of whoever is behind you burying their vehicle into you. Just move over.


Back to the subject at hand - One of the things that drives me nuts about this feature is that I like to modulate thru curves in bad weather, and every once in a while the assist kicks in as I'm going around a bend. I had one instance last winter where it kicked in during a controlled skid (obviously on an empty road) and very nearly put me into a rock wall. Thankfully the snow was deep enough to slow me down to the point I could recover before going in ass-end first.


That said, I like pretty much all the other drive assist features. The traction control is amazing -- it's like anti-physics. Zero skid with that thing on - ever.

 

[1engineer]

Not to mention if you get nabbed riding right in some states it's not only a $300 failure to yield ticket, but another $50 surcharge, and 2 points. The good old "brake check" can get you slapped with a reckless driving charge - max 3 months in jail, mandatory $500 fine, 5 points. Plus the risk of whoever is behind you burying their vehicle into you. Just move over.


Back to the subject at hand - One of the things that drives me nuts about this feature is that I like to modulate thru curves in bad weather, and every once in a while the assist kicks in as I'm going around a bend. I had one instance last winter where it kicked in during a controlled skid (obviously on an empty road) and very nearly put me into a rock wall. Thankfully the snow was deep enough to slow me down to the point I could recover before going in ass-end first.


That said, I like pretty much all the other drive assist features. The traction control is amazing -- it's like anti-physics. Zero skid with that thing on - ever.

That's not brake assist kicking in, that's your Vehicle Stability Control. If it's kicking in when you are not skidding then you need to have a Zero Point Calibration done. This is common when suspension parameters have been modified, such as lifting.