Brakes - Scared the SH!T Out of Me

Sounds like you tapped the brakes so hard that the ABS engaged. The sounds and pulsating you describe are typical of an ABS working.

 

Any bumps or chuck holes in the road? Hitting a bump can force the system out of regen and into ABS braking.

Tom

 

Bumps in the road have caused this for me. It seems when the wheels 'leave' the road causing a sudden change from thier current spinning pattern the ABS appear trying to regain control.
It happens a few times for me, usually on the same stretch of road.
first time(s) scarey - you'll get used to it after a while.

 

toms suggestion is valid as hitting a bump or series of them will trip the ABS, causing it to vibrate as you applied the brakes.

also, did you spray some armor all or tire dressing? this can cause an initial strange behavior from the pads.

 

ok, then tell me the light changed suddenly when you were less than ½ a block away and i could understand it.

but you really should have been easing off the speed much sooner, light touch on the brakes to

1) save friction brakes
2) maximize regen (might as well since you have to stop somehow)

but as far as that feeling goes... were there any manhole covers??? because i have had that happen to me a few times and its because those manhole covers is like being on glare ICE...around here we have a few on the road in a traffic circle which i guess i find hard to understand (there is a middle area which would allow maintenance without any traffic holdups...but then again, i am not a traffic engineer so what do i know??)

 

You won't see a massive recall because of this issue. ABS from a bump or manhole cover is well known from the Gen II Prius. It is simply one of the quirks of regenerative braking and the HSD system, and is mostly an issue of perception. Once you know about it, it's not a big deal.

Tom

 

i agree. other than the momentary shock to the senses which realistically lasts about 28 times longer than any danger imposed, its really a minimal issue.

i live with wet roads 8 months out of the year. after a while, you get used to it. can anticipate it, etc.

 

Possibly oil on road?

 

A bump in the road can activate ABS on any car. You'll be laughed at if you suggest that this will trigger a massive recall.

The difference is that the downshift-like regenerative braking of the Prius cuts out when ABS kicks in. It seems like this transition could be made smoother by Toyota, but then maybe that would cause other problems.

I haven't experienced this yet, but now that I know about it, I'm a bit more prepared. I'll have to brief my wife, who doesn't drive the Prius much but will be driving it for over a week when relatives are in town.

 

This happens in my Honda Odyssey as well. When I first got it thought it was unusual, but now used to it.

 

ABS by definition only works if coefficient of friction is pretty much constant since that is how it judges how it will brake.

with multiple road surface conditions (on those like 18 inch wide white crosswalk markers, i can spin my tires on them, just hard to time it right...but have done it before on my Zenn) having smooth effective braking is not gonna happen 100% of the time, but we dont need it that often anyway... 99.5% will be ok.

the OP has a valid concern because the first few times it happens, it does give you a jolt... but still pretty much harmless (as long as your heart is in good shape that is!!)

 

While ABS systems have gotten better, since I got my first one (in a brand new '96 Blazer) they've always been easy to fool with braking on railroad tracks, bumps, etc.

This is really a case of "its a feature" and not a bug. When something on the road forces the tire to loose traction while braking, the result is that wheel keeps spinning faster than the other wheels that are braking. The ABS is programmed to interpret that as a spin/slip and initiate ABS braking procedure. The sensitivity to this has been reduced over the years by most car makers, but at the expense of not kicking in until there is a more significant amount of slip. Some conditions like heavy snow have also been known to fool the systems (most newer ABS systems evade that by only allowing 'x' number of activations within a set time frame, hence self-disabling in heavy snow).

I always advise someone when driving a new car with ABS to do one controlled (safe) panic stop, so you become familiar with the braking system.

Though if you try a panic stop in a Mercedes/smart be prepared, they have the feature where they judge the speed at which you press the brake, and if it reads as a panic stop, it presses the brake HARD DOWN for you. Though it does make the car stop so fast you think you threw an anchor out the window. ;-)

 

Tried this earlier today, and it was a bit startling. It sounds much higher in pitch than any other ABS system i've heard, which would indicate that it applies/releases the brakes much faster than the older systems i'm used to.

Neat!

 

The Prius also has this feature. It works shockingly well.

Tom

 

Makes sense everyone else would adopt it. Mercedes has never enforced a single safety related patent and allows anyone to use them.

 

Those that choose to use profane words to get their point across simply lack a more educated form of expression. This does not mean they should be labeled as "narrow-minded" but perhaps "linguistically challenged"


BMW has this as well......

 

Wth does this mean? I hate it when dumb A$$ people drag this big-worded s*#t into f***ing conversations.



Tom

 

:thumb: