I finally had the opportunity to try the hill start control function of HSD. I was coming out of an underground parking garage that had a very steep entrance up to the street. There was a line up a cars leaving so that meant having to stop right in the middle of this fairly steep incline. I knew the car had this feature so I gave it a test. I let my foot off the brake and paused for a second or two and the TCH didn't budge until I applied the accel. pedal.

This incline was steep enough that any car without some sort of "hill hold" system would require the driver to be very quick and alert to avoid falling back into the car behind. A succesful test.

 

Please explain further. You just took your foot of the brake pedal while stopped on a steep up-hill, and the car didn't roll back?

 

Here's a link to the description of the system.

http://www.hybridsynergydrive.com/en...t_control.html

 

Would this be part of the stability & traction control system?

 

wow! Even more tech wonders! This car is simply amazing! (well, not that simple afterall!) Thanks for the tip, Andy!

 

Excuse my ignorance (there's a lot to excuse). I've driven manual transmissions where that would be a problem. But I don't think I've driven an automatic that would go backwards when in Drive. I would think that would harm the transmission. What am I missing?

 

Interesting. There is a 'feature' in the 2004 Prius referred to as 'creep'. Austensibly so people wouldn't freak if they took their foot off the brake and the car didn't move forward (on a flat) as they would expect from any other automatic. If there is a balance of 'idle creep' and hill slope, it won't roll back. No different than any other automatic. The link shows a Prius and the 'hill holder' concept seems to generic to HSD. My '04 has slope sensors so maybe this is an improvement for the '06 (maybe '05, don't know) HSD. Another cause for '06 Prius vs '04 envy

Subaru has a "hill holding clutch". The brakes will stay on when you remove your foot until you start to release the clutch. Very helpful on hills. I needed to use the hand parking brake in my manual '86 Mazda for steep slopes.

 

An automatic in "D" can still roll backward at idle on a slope.

 

I didn't realize that, but there are no hills here so I guess I'm excused.

 

This was a big problem for my 99 Corolla on very steep hills. Of course, it wouldn't be as much of a concern if people would not tailgate other people, especially on hills. I mean, if I can see the guy's uvula when he yawns in my rearview mirror then he's probably WAY too close to me....