Has anyone noticed when driving a bit hard, and coming up to an intersection where you have to brake pretty hard, that if the road is chopped up or bumpy, the brakes suddenly release slightly and allow the car to coast a bit, requiring additional pedal pressure.... Nothing I can't deal with, but feel there is an issue with the road surface bumps messing with the computer controlled regen braking vs use of the brake pads..

Anyone else notice this? It only occurs if you brake pretty hard and the road is rough.

Other than that, 12K miles in 8 months and averaging about 36 mpg. Overall has been a great car.

 

Yes, I notice this too, although I don't need for the road to be bumpy at all. In fact, Inotice this most often on the freeway when traffic suddenly slows down. This has occured on parts of the I-5 Fway that are both smooth and rough.

 

I have noticed this on occasion. On the other hand, once a dog ran out in front - panic stop was smooth and fast - I was amazed I was able to stop without hitting the dog. If I had been driving my truck the dog would have been a goner...

I have also noticed the TCH brakes seem to respond to how suddenly the brake pedal is pressed, even if only slight pressure is applied. I'm used to my truck where I need to get on the brakes quickly to be able to anticipate and react if the traffic suddenly changes. When I do the same on the TCH, the brakes jerk the car comming on stronger than I expect, then within a second release to light braking - without me changing pressure on the brake pedal. I'm adjusting to the TCH, but it is irritating when it happens.

 

if it's what I'm thinking, it might also occur when you brake over a wet manhole cover or wet railway track.

 

It sounds to me like your ABS is kicking in.

Rippled or un-even pavement while braking can causing inconsistent rotational speed between the wheels. This could be read by the ABS system as an impending lock-up. The corrective action is for the ABS to starting modulating braking force on the wheel it 'thinks' is about to lock up.

 

The regenerative braking forces are very strong in these cars. So much so, that if left unchecked they would interfere with proper ABS implementation.
If the vehicle senses an emergency situation, it will turn off/reduce the braking regen in order to allow the ABS to function properly. This creates the sensation of acceleration. Often if your foot is not in emergency mode (ie. max pressure on the brake pedal), it is necessary to press harder on the brakes.
I used to feel this quite often when the car was new (HiHy). Now I barely ever feel it. BTW, the car stops on a dime when I need it to.

 

This symptom is very common among Japanese Prius drivers too.
We also believe it is caused that the ABS system detects the slippage wheels and Prius abandons the regenerating, so you feel less braking power.
We found we can recover this situation by shifting to B, then we can see the regeneration again.

Ken@Japan

 

I lift my foot off the brake & reapply to reset the regeneration. Of course this is done only when it can be done safely.

 

This sounds like what happens to me. You feel a bit of what you would think is ABS. But I believe and I think it was mentioned before, this is most likely moisture on the pads because the mechanical breaks are so seldomly used. I was worried when it first happened and tried to recreate it but was unsuccessful. It is random and usually the first full stop of the trip (or one of).

 

I had something similar happen the other day but I was driving for a while at low speeds through the neighborhood and came to a slow stop with little pressure on the brake and it felt like the ABS kicked in very hard. This was dry pavement,sunny day etc. Never happened again. Any thoughts?