My Prius saved me from a serious accident

thanks for the report, glad you are okay!

 

I'l glad to hear you avoided an accident but one shouldn't be surprised by the cars' braking ability because every driver should periodically practice braking to the limit. It's a known phenomenon that some drivers will actually release the brake pedal when they feel for the first time the unfamiliar hard pulsing of ABS activating and collide with the object they were trying to avoid.

 

Glad you got away from something like this. People are driving crazy now days. I got hit twice waiting for the green light .it can happen to anybody.

Posted via the PriusChat mobile app.

 

Glad you're safe & sound mate!

This week, I was driving in the city around 20mph and there is a car momentarily stopped in traffic but was about to move away again. As I approached, my Gen 4's sensors made it believe I was at risk of crashing into that car, and even though I was slowing down with the foot brake, my Gen 4 added some extra effort to the braking process, which was not an emergency stop but was a noticeable form of assistance.

I can't remember what the formal acronym is on the Gen 4, but useful to know it's there to step in.

 

The 2010+ cars in my household (Prius and another brand) don't exhibit that old-fashioned ABS hard pulsing. Their ABS's are much smoother than on my previous late-20th Century car.

The BA (Brake Assist) in my Gen3 Prius is excellent at detecting a panic brake event and maximizing the stopping power. On dry pavement, it almost feels as if it is trying to pull the pavement up from the roadbed. Gen4 ought to be at least as good, if not better.

 

Toyota calls it PCS "Pre-Crash Safety System". If the system detects a potential front crash, it warns on the screen plus a buzzer, and increases brake pressure - if no driver action is taken, it then applies the brakes itself.

I've noticed that the couple of times it has displayed the warning and buzzed, and I've braked, the brakes are quite savage, with them pre-primed for action. I'm not convinced the brakes are any better, if as good as, my last 2 cars, both small FORDs with low profile more sport type tyres (Continental, I think).

Read about it in your MANUAL - in index under PCS.

 

PCS and BA (Brake Assist) are different systems. OP could well have triggered the BA before the PCS system decided to go on alert or take its own preemptive action.

 

I wonder about BA - there is only a 2 line mention of BA in the manual - but 14 pages on PCS. I suspect that PCS triggers BA as well - I'd be surprised if they work independently of each other. My previous car indicated that ABS and BA systems were complimentary to each other, so PCS could well do too.

 

The other day I was at 60MPH and the guy leading a group of 4 or 5 cars slow up almost to a stop. For no reason. The brake light came on. me or the Prius locked up the front tires. Amazing braking at that speed. All was fine. I don't think my old Gen 2 would lock up the tires at that speed.

 

ABS should stop locking any tyres - a rolling tyre has far more traction (as well as control) than a locked up one.

 

When ABS was first becoming "a thing", Motorola semiconductor produced a brochure outlining what their IC did for it. For example, they mentioned that peak braking force occurs at a tire slip rate of around 30%. So their chip was set for that peak braking force slip rate. Even at that slip rate you can "steer around" the object you were about to hit.

Don't be too hard on the moron. We all make mistakes. I learned early on seeing IS NOT believing, believing enables seeing (as I turned left right in front of a car I did not believe was there)!

 

Everytime I try to Brake on my Gen 4 I don't fully trust those Brake . My dealer checked them they seen fine. It just feel like I going to hit the car in front of me . Maybe I am getting flash back cause I got hit twice waiting for the green light.

Posted via the PriusChat mobile app.

 

Brake assist (BA) or emergency brake assist (EBA) works on how fast you press the pedal, not necessarily on how hard you press it.
If you tap the brake pedal lightly but quickly, the EBA will operate, if you press the brake slowly but hard EBA will not activate.

 

Yes it locked up the wheels. I've done it a few times. Defiantly not a long skid. As to the ABS, my last car that had ABS, did the typical modulating the braking to the stopped wheel. I have been waiting for some snow to see how it behaves. So far no sign of the typical ABS chatter noise.

 

Dragon, it think I know what your feeling. At times when applying the brakes there is a dance the between regen and running the ICE. It feels like a loss of braking. In my gen 2 it wasn't as noticeable. And then there is the transfer from regen the mechanical brakes at 3 MPH. Actually the gen 4 does this much better than my gen 2. But good news, when I went hard on the brakes at high speed, they worked well.

 

Ah - a bit like playing the piano and the hammer velocity vs hammer force (and hammer hardness for those with poorly maintained pianos).

 

I've noticed the same - I'm inclined to think that with GOOD tyres, not good economy tyres, that the brakes would behave more like a normal car. I tend to keep my cars for 3-4 yrs, and generally sell them about when they need new tyres - so I don't think I'll be trying it with "normal" tyres.