don't use B mode in heavy traffic

Where I live, there are numerous hills that will charge the battery to 80%. I use B for those areas all the time. Never in normal traffic though. I don't want to throw that kinetic energy away. I would rather convert it to electricity and store it in the battery.

 

I don't think the OP is at fault for anything. The idiot behind him is the one at fault. Hell, under normal deceleration I've been at risk with someone riding my rear bumper. Then if you pulse your brake lights you're an arseloff. People are just driving around in H. I.A. mode all the time.

 

I'm surprised your Prius had no damage, the rear bumper cover is notoriously paper thin. Seems like if you just look at it wrong, it dents.

 

How have you measured the amount of braking from the ICE, with a full battery, in D vs B modes? The only thing I have to go by is how it feels and how many RPM the engine is turning. I can look at the tach and the speedometer for RPM vs road speed but the amount of braking without measuring G forces is totally subjective. You may be right but as I recall it's about the same in either D or B providing the speed I am maintaining is about the same.

 

I suggest you have your car checked by a shop before thinking it has no damage. Often times the real damage is underneath the bumper covers.

 

It isn't necessary to measure actual braking force or Gs to distinguish the difference. On an appropriate hill, switch back and forth between D and B and make note of the differences displayed by:
* Butt dyno;
* RPM;
* Speedometer.

If you are maintaining speed in D mode, while your foot is off the 'go' pedal, then the hill isn't steep enough. The hill should be steep enough that the car 'runs away', gaining speed from gravity alone.

For some range of steepness and speed, the car will gradually gain speed in D mode, but lose speed in B mode. On even steeper hills (e.g. the 7% grade on US 95 at Lewiston ID), both modes gain speed, but B gains slower than D.

 

We've had our car closing in on 3 years; I can't think of one instance when I NEEDED B mode. Came close maybe: coming into Whistler from the east, but even then, it was all ok

 

B is the nearest we have to shifting down and yes there would be times when it's foolish to shift down instead of braking.

 

It is B because some one at Toyota was too honest to call it L.

Toyota is legally required to have a gear like B.

 

Thanks for the reply, I'll check it a little closer next time I'm in the mountains.

 

I use B occasionally because I just hate heavy brake use at speed. I know, it's inefficient. Consider it PEV practice.

There's also some proper use where we a steady descent. Not many and I like to avoid that because it means we went up a lot to get there.

OP could be considered to be at fault, depending on state law. In Maine drivers are required to avoid accidents.

If it's clear you have a tailgater you really shouldn't brake rapidly without a working taillight. The whole problem with tailgaters is that they don't have enough reaction time.

 

Don't. Minimize your tendency to do dangerous things! It helps in other aspects of life as well.

 

I wonder if this technique is why I see 100 to 1 Prii smashed in the front.

 

Some people just over-think the whole Prius driving. Drive it like a regular car for the best results. This how it was designed, to emulate a normal car.

 

Considering that OP had to stop, with real brakes and brake lights, to avoid colliding with the car in front, my state would not hold him at fault for the collision behind.

The Prius B mode does not slow the car so quickly that a driver at minimum legal following distance, and being adequately attentive to the traffic situation, should have a problem stopping in time to avoid a collision. I'm well aware that this 'minimum legal following distance' does not reflect the reality of congested urban traffic in many areas, but that doesn't change fault.

 

I don't quite understand, how Prius slowing by B-mode is going to get front end damage, lol.

Likely the reasons for front end damage are:

1. The spectacular front end crumple zone.
2. Cabbies.

 

I agree.

Why people want to be "Clever" and use it for other things is beyond me.

You bought a Prius.
You bought a highly engineered vehicle.
Don't try to out think the HSD system.

Put it in D to drive, P to Park and only use "B" as recommended in the owners manual. How hard is that?

 

By people thinking this is a viable way to stop the car.

 

All the energy you used to spin the engine is wasted, the energy you get in regeneration, you would have gotten at least as much by pressing the brake pedal. Above 24 MPH there is never a 'win' in B. It is a safety gear, not a fuel saving gear.