Brake Assist helped me avoid a crunch

[MicaBlue03]

'Till now I hadn't thought much about this feature, though I felt it had activated on me once or twice in 3 years. Yesterday I had an enlightening experience.

I was moving at about 25 MPH, about to go straight through an intersection, and was traveling next to cars in the left-turn lane. The turn arrow had just come on (the light had been green in my lane for a while, hence my speed) and so the cars in the turn lane were slowly accelerating, perhaps to 10 MPH.

As I was about to come up beside a minivan that was in the turn lane the driver abruptly started to veer to the right, into my lane. I had no time to do anything but brake hard and steer carefully to stay behind and between the bozo in the minivan and the cars in the lane to my right. The minivan came about halfway into my lane before veering back into the left turn lane and eventually making the turn. Somehow I avoided crunching sheet metal on either side--fortunately the car(s) to my right weren't too close to the left edge of their lane and I was able to slow down enough. It was only after the minivan driver got back into her lane that I had the chance to honk, but that was too late to do any good.

Here's my point: This happened so fast and steering was so important during the incident that brake assist was likely very helpful. I was so busy detecting the problem and steering precisely that I didn't have the chance (or spare share-of-brain) to optimize my braking. I'm not at all sure that I would have gotten the full effect of ABS in this situation because I don't habitually stomp the break pedal fully in emergency stops. ABS wasn't around during most of my driving years so I might not remember to hit the pedal hard enough, especially when it's not just an emergency *stop* and I'm focused on steering out of trouble.

So I think the brake assist feature was a real help in this case, as it got me into a max-stop mode as quick as possible, and kept me there while I steered, and until I lifted way off the pedal.

I still have no idea why this woman did what she did with her minivan. Dropped her phone? Changed her mind? Lost her mind? Sometimes all the closure you get in these incidents is that you survived without bending something.

 

[OUTRNNR]

I still think BA is useless, just in case you care...

 

[Kmvreter]

I still think BA is useless, just in case you care...

Either you are very sarcastic or you are raining on his parade. Obviously MicaBlue03 thinks otherwise.

Mica,
Good job not "bending metal". Glad it worked for you. It's helped me once in the past when a bozo turned into my lane from a side street. He obviously didn't see me or didn't care but he heard about it. The cops picked him up for impaired after I called in with his tag number.

 

[Fourty-four]

I find it strange that your natural reaction is not to hit the brake pedal hard. If I were driving a new vehicle or an old vehicle without ABS, Brake Assist etc.. my first reaction would be to mash the brake pedal as hard as possible if I were about to crash.

How could it not be your natural reaction?

BTW, brake assist was developed after it was determined during a study that a significant amount of drivers do not apply enough force to the brake pedal to fully take advantage of the vehicles stopping power. It's not that they don't have the proper reaction, it's that they either don't have the leg strength or they don't know that they can get more braking force if they really stand on the pedal.

If brake assist helps prevent accidents, then I'm all for it. After all, I don't want that blue-haired old lady behind me crashing into the back of my 4Runner!

 

[Thai]

If brake assist helps prevent accidents, then I'm all for it. After all, I don't want that blue-haired old lady behind me crashing into the back of my 4Runner!

Well, the small problem with BA is that it may cause an inattentive driver behind you to rear-end you because of how quickly you stopped due to BA. Of course, it is always better to be rearended than plowing into someone from the insurance (and cop's) point of view.

Let's just hope that the car behind you also has BA...and the one behind that one...and the one behind that one....:

 

[dwulffusa]

Dont like BA or the electronic throttle, both make driving in stop start traffic a pain. I find it takes a lot of effort to modulate both pedals to get smooth pull aways and stops. I have posted on the overreactive breaks before but it seems that not everyone has this issue. It is sensitive to the point of being a struggle to predict what pressure it is going to apply based on the speed my foot touched the pedal and not the pressure I placed on it.

Here's a scenario that enfuriates me : Coming up on a traffic light perhaps a little fast, light goes orange, I climb on the breaks in jault, knowing I still have plenty distance and enough grip on the tar not to need ABS, well the BA thinks I do and goes into full breaking, my foot isnt even mashed to the floor, so I ease off the pedal as this harsh breaking will leave me short of the light, but no less break force results, ease up quite a bit more and the breaks release all together for a split second so I reapply pressure only to have the same full breaking BA effect and it looks like I am see-sawing to the light, repeat the same, OK for fsakes - come right off the break pedal and reapply, breaking is smooth now, but I come to stop 2-3feet into the intersection as I had to come right off the breaks to let it reset itself. I hate this damn feature.
Go ahead and try this scenario in an empty parking lot and for fun, add a little drizzle to make it even more sensitive, I am sure alot of you will get the same result.
I am not knocking the safety aspect of it, and it works well I suppose for majority of drivers out there who are not able to determine the dynamics of the vehicle they are driving or assess their speed and limits of breaking and grip in a given emergency situation, but for me this is a thorn in my side that I would like the option of switching off along with VSC, seatbelt warning chimes etc etc.
Now where is the mapping for these mods on the ECU?!

 

[Koz]

Regardless of what anyone has to say about this feature, it is a life saving safety feature and the safety it provides far outweighs the little inconvenience of when it engages unnecessarily (which is mostly caused by a twitchy foot - overreacting). Also, THANKS for sharing your experience with us!

Koz

 

[Kmvreter]

Here's a scenario that enfuriates me : Coming up on a traffic light perhaps a little fast, light goes orange, I climb on the breaks in jault...

I see 2 possibilities here.
First could be your driving style. Slow down, drive defensively. I've never had the BA kick in during regular stop & go driving (the same scenarios you described) and I have a lead foot at times.
Second could be a malfunctioning system that is overly sensitive. The system may not throw an ECU code because it thinks it is doing what it is supposed to based on your inputs. If you are under warranty then see what the stealer says.
Do you also suffer from the driveline clunking others complain about? This is the axle releasing after wrapping up under heavy braking. This points to the first part above. Anticipate ahead and change the way you stop.

 

[nated05]

Ive noticed BA kick in only once or twice, and both times it helped me stop before plowing into someones rear. I personally like this feature and agree with Koz that it has more benefits that annoyances.

dwulffusa, im not sure how long you have had your truck, but I had the same issue when I bought mine. The brakes were way more sensitive that what I was used too. It took me prob. about a month to get used to stoping without practically throwing myself through the windshield. Now after over a year I have absolutly no complaints about the brakes.

 

[toto]

I have noticed that the BA on the 4Runner is a bit more sensitive than the BA on an RX 330. I got used to it on the RX, and it only kicked in at times when it was appropriate - mostly sudden stops in traffic or to avoid kids running into the street. It seemed to work based on a combination of speed and how hard I hit the gas pedal. The one time I've experienced it on the 4Runner was on the test drive, when a rabbit jumped in front of me at about 30 MPH. Even though I was already used to BA, the truck stopped so quickly that I thought I'd eat the windshield! (Exaggerating, of course.) I was truly impressed by how quickly and the short distance in whcih the truck stopped. It's great to know something like that is there when you need it.
I agree with the comments above that the key to normal driving is to begin braking early enough so that you're slowing down gradually. Not only does that keep you from hitting something, but it also gives the folks behind you more time to see brake lights and slow down. Just because you can stop on a dime at the next light doesn't mean the car behind you can. Believe me, it's not much consolation to be the person in the accident who was "right" and not at fault - your truck is still smashed up.

 

[Bluto]

... the truck stopped so quickly that I thought I'd eat the windshield!

It has surprised me a few times as well.



The few tenths of a second BA can give you full braking power (compared to fully depressing the brake pedal) can make all the difference in an emergency.

65 mph is 95 ft/sec. Rear end someone and I bet you'll wish you had the extra 10-20 ft BA would have got you.

 

[sharp4runr]

I like the brakes on the 4Runner a lot. I guess I'm used to the sensitive brakes because my previous Celica had brakes the bit hard too. The Celica didn't have ABS though so I really like the brakes on the 4Runner

I wouldn't change a thing.

 

[OUTRNNR]

...Here's a scenario that enfuriates me : Coming up on a traffic light perhaps a little fast, light goes orange, I climb on the breaks in jault, knowing I still have plenty distance and enough grip on the tar not to need ABS, well the BA thinks I do and goes into full breaking, my foot isnt even mashed to the floor, so I ease off the pedal as this harsh breaking will leave me short of the light, but no less break force results, ease up quite a bit more and the breaks release all together for a split second so I reapply pressure only to have the same full breaking BA effect and it looks like I am see-sawing to the light, repeat the same, OK for fsakes - come right off the break pedal and reapply, breaking is smooth now, but I come to stop 2-3feet into the intersection as I had to come right off the breaks to let it reset itself. I hate this damn feature...

:iagree: If you can't push the brake pedal hard enough to stop in an emergency braking situation to fully engage the ABS you shouldn't be driving. Go do some calf raises and squats then try again. This "feature" has nothing to do with driving too fast or not driving defensively nor does it have anything to do with not fully engaging the ABS when you push the pedal to the floor, providing you have the strength to do it. The way BA works is simple: The computer is programmed to recognize two things; a quick jump off the throttle and to the brakes and a quick partial engagement of the brake pedal. What this tells the computer is that there is a person driving who doesn't have enough strength to push the pedal down, and applies full power to the braking system. That's it! If you push the pedal to the floor yourself BA does NOT activate because it doesn't need to, that way you decelerate at YOUR desired rate instead of eating the dashboard. How would I know? I've had the luxury (a couple times) during driving of pushing the pedal to the floor during an emergency stop, and never once was I suprised by BA, I could feel ABS working, but no annoying BA. The only time I've had it activate was useless times in traffic resulting in a near rear-ending by the person behind me, and I could've gotten the same effect by jabbing the brake pedal to the floor a couple times.

If you think that BA buys you 10-20 feet of braking distance under FULL engagement of the brake pedal you are sorely mistaken and should erase that thought from your mind when you are driving. No way in hell would Toyota reserve an extra 10-20 feet controlled by the computer. Additionally, if you can muster enough strength to push the pedal to the floor, you can feel ABS working under full power, which means the car/tires has reached its traction limit anyways - its not like BA is going to magically increase the stopping capacity between the tires and the road; Come on, its just Physics!!

There are many situations when I drive, and it's the way I've trained my foot to react in braking situations, when I meet the requirements for BA to activate and I've tried adjusting my braking style and always keep it in the back of my head.

Don't get me wrong, the 4Runner has one of the best performing brake systems that you can buy on an SUV today; 4 wheel discs with large 13.3" rotors and 4 piston calipers up front, it has the stopping capacity of a sport sedan. 70-0 in 170 feet is on par with some sports cars. BA ruins that authentic braking control and can create dangerous situations when it engages when it doesn't need to. However, I'll agree that yes, in more situations than not it will probably do good, but not for this guy. If I could find the fuse or somehow otherwise disable the system, I'll be the first one to do it...

 

[Koz]

I have not heard or read one instance of a scenario where the BA was not working properly. When someone hits the brake pedal quickly regardless of weather it is or not a panic stop the system engages and will stay engaged until you fully release the pedal. It's like the bell was rung, you can not un-ring it. You triggered it by quickly hitting the pedal. The 4Runner has the best brakes I have ever felt in a truck. I think the system seems very sensitive to the quick hit because the brake

 

[Bluto]

If you think that BA buys you 10-20 feet of braking distance under FULL engagement of the brake pedal you are sorely mistaken and should erase that thought from your mind when you are driving. No way in hell would Toyota reserve an extra 10-20 feet controlled by the computer. Additionally, if you can muster enough strength to push the pedal to the floor, you can feel ABS working under full power, which means the car/tires has reached its traction limit anyways - its not like BA is going to magically increase the stopping capacity between the tires and the road; Come on, its just Physics!!

Is is not what the computer does, but how fast it does it. With BA ABS will fully activate before you can fully engage the pedal. The computer is faster than your foot. It is reaction time, not physics.

 

[GYoter]

The only time BA kicked in for me was when i was towing and some a-hole pulled out right in front of me. I stood on the brakes(not breaks) and definitely felt the BA kick in more. I was surprised at how fast it stopped with 3500LBS in tow since i thought i was going to plow the back of a suburban. Now im sure i would have stopped just fine w/o it, but in this situation it was quite nice to have.

The system may have been thought of for the soccer moms that are small and cant physically press hard enough to stop the truck, but there are legitimate situations where it can help anyone.

I am by no means a "mellow" driver but still I dont know what some of you do to have it kick in during every day driving, you must be jumping on the brakes way more often then the standard person. In daily driving i have never once had the BA kick in.

 

[Casper]

Good to hear that it kept you out of trouble brother..



Though I must say that I hate it...being that I have already upgraded the pads, fluid and lines in the system; BA kicks in much sooner now and much more violently. To add to that, because the system is now much stronger, the BA doesnt wear off as fast as it did before. I would love to deactivate that crap.

 

[Kmvreter]

I am by no means a "mellow" driver but still I dont know what some of you do to have it kick in during every day driving, you must be jumping on the brakes way more often then the standard person. In daily driving i have never once had the BA kick in.

I agree.

 

[OUTRNNR]

Is is not what the computer does, but how fast it does it. With BA ABS will fully activate before you can fully engage the pedal. The computer is faster than your foot. It is reaction time, not physics.

OK, I'll agree with you there, but you have to admit that any normal person can stomp on the brake pedal pretty damn fast and the difference in time between when the computer recognizes a BA situation and engages BA and when my foot reaches the floor is measured certainly in fractions of a second, perhaps milliseconds, which does NOT translate to 10-20 feet at any speed that the 4Runner is capable of acheiving. A foot maybe, inches maybe, which yes can make all the difference in the world, but lets not fool ourselves...

 

[Koz]

The whole design and purpose of the system is when most people are in panic/emergency situation they hit the brake pedal and as soon as the ABS kicks and does not allow the wheel to lock (especially in the rain & snow) the normal/first reaction is to let up on the brake pedal. The BA kicks in to provide the maximum braking power as long as you have your foot on the pedal.

Koz