Autostop on a hill and rolling backward.

[davidm]

Has anyone else noticed this? If I'm stopped on a hill facing uphill and autostop is on, when I take my foot off of the brake to move forward again I momentarily roll backward before the engine kicks in. Neither the brake nor the engine are counteracting gravity.

This could be a problem if someone is sitting too close to your rear bumper.

I've found a solution to this. When it appears that I'll be moving soon (traffic has started moving, the light changes, etc.) I let up on the brake slightly then push back down on it. This starts the engine while maintaining braking. I can then move from brake to accelerator without rolling back.

[insightfulone]

I noticed this once when the car was new. I rolled back while exiting a parking lot on a steep incline, far enough that it was disconcerting and a problem if someone was right behind. It hasn't happened again. I think the timing must be just right, not long enough for the antislip to set in, but long enough for idle stop start. Lightly releasing the break to start the engine is good solution, thanks for the tip

[davidm]

Its' a bad situation. Potentially you could roll into a pedestrian.

I'm sure there's some design change that could be made that could prevent this. If nothing else a tilt sensor could prevent autostop if a hill is to steep.

[livfreely]

It has done this to me as well. Like david said just hit the brake again. I did this out of instinct and made it through. I don't think this is going to be to big of a problem though. As long as I'm aware of it.

[davidm]

The problem is that, if you're not expecting it, you could roll into the car behind you before you have a chance to hit the brake.

You need to let up on it just enough to restart the engine without actually taking the brakes off completely.

[Roger B.]

i thought this car had brake assist to prevent this on minor hills. i thought i also read in the owners manual that auto stop was not supposed to work on steep inclines. at any rate shifting into low gear should also restart the engine, eliminating having to slip the brake.

[davidm]

Maybe so but I know what happened.

Isn't letting up on the brake easier than shifting into low?

[Cobb]

I suffer this as I ride the brakes to a stop. If you press the brake firmly once stopped it will reduce this. The prius 3 I rented did the same thing.

[davidm]

Cobb,
Maybe I'm misunderstanding you, but I'm not sure that you're describing the same phenomena. What I'm talking about is something that happens on a hill in the moments between when I release the brake and the engine comes out of autostop.

You're talking about riding the brakes to a stop which sounds like something different.

[Cobb]

If I ride the brakes to a stop, the car will roll back when I go to take off. If I stomp the brake petal once stopped, the car will not roll back when I let off the brakes.