don't use B mode in heavy traffic

Yes, it is actually.

FYI, it's brake and braking.

SCH-I535

 

Besides the traffic hazard, it is also a slightly wasteful energy practice. Some of the potential energy recovery of regenerative braking is thrown away as engine compression braking.

My first Prius was also hit in a similar highway traffic situation, but not for the same reason. Gradually slowing traffic, just enough to light up everyone's brake lights, turned into a sudden stop, with no change of brake lights. I stopped fine, as did the guy behind me. But the teenager behind him, with a car full of other teenagers, didn't notice in time and caused a three car chain reaction. My spouse was momentarily in a panic that our relatively new car was very seriously damaged, but it turned out to be only the a nose imprint of the middle car on the rear bumper cover.

 

B mode depends how you use. I used it without any issue or incident/accident. The civic tailgating you should be fxxx. Those civic, getter ..guys are always think we Toyota drivers are slow, stupid and tailgating to give us pressure which is disgusting. Those guys should be blamed.

 

I try and avoid the B whenever possible for the reasons the OP posted.

 

B mode is really only for going down steep hills IMO.

 

B mode is fine for long steep descents, but is a fuel waster above 24 MPH. And yes, since there are no brake lights, it is dangerous in traffic.

 

Why the fuel waste? AFAIK in "B" mode the ICE acts as compressor - is the gas still delivered to the manifold or the electromagnetic valve close the fuel flow?

 

If you were NOT in B, you would store more energy via regeneration, so you would have more stored energy and not use fuel. Toyota is not storing the compressed air to power the car later.

 

Is down changing gears dangerous in traffic?

 

Pity
I meant.. when the ICE is operating during "B" mode some would say that it consumes the gas - which I don't think so.

 

It doesn't burn gas at that moment...however it wastes energy that could be captured with regenerative braking for later use.

 

a) if you can shift gears in your Prius, I am eager to hear about it.
b) in a manual transmission, if you slow without brake lights, sure.

 

Fixed

 

Use your brakes. That why you have them. "B" is just for reducing some of your speed on a descent and is a waste of energy when used as you have described.

 

Rookie mistake, but hope you learned from it! Glad your prius was not damaged. Sometimes in our enthusiasm to try to squeeze the most out of the Prius, or to save gas we do dangerous things. I am guilty sometimes as well, but I am trying to minimize my obsession to sometimes squeeze the most out of a gallon of gas.

 

IMHO the only time it makes any sense to use B Mode is when the battery is completely charged and you need to slow down, such as descending a long steep hill. Actually even under those conditions you don't need B Mode. You can still use the brakes in the regenerate portion of the HSI and if the battery is full it will automatically use the ICE as an air pump (just as if you had selected B with the shifter) to help you slow the car.

 

He meant for the whole driving cycle, not for that particular moment alone.

 

Some hills still do need B Mode. Yes, D mode will perform as you describe, but produces weaker compression braking than B, too weak for numerous hills. (Even B is too weak in some places).

B mode also allows the driver to begin compression braking before the battery is full, useful on long hills where the battery will fill up anyway and the driver's ears would like to reduce the amount of that high rpm jet engine roar.