I realized today that a lot of the unexpected braking I'm getting isn't the FCW at all, but the ACC. I counted something like 5 inexplicable slowdowns today on the way to work, a couple when the car in front of me moved into another lane, once as I approached a bridge, and even once with no car in front of me (and no filled in 'target acquired' car on the dash).
It happens often enough to be a frustration, but I'm beginning to change my mind about whether it is acceptable. With that number of unexpected braking events in a given trip, it's entirely possible the ACC could lead to a lot more impacts than it would prevent. Of course, to the extent they are cause by people behind you not expecting you to brake, they might not show up in crash data as the "fault" of the Clarity.
Not that there are enough Clarities (Claritys?) to get meaningful crash statistics.
I have also noticed that sometimes applying the gas with the ACC on can result in the car to slowing down, which is super counter-intuitive. My guess is I'm not applying as much throttle as would be necessary to maintain speed, but because I'm depressing the gas pedal, the ACC is deferring to my foot.
This is really noticeable right when I turn on the ACC, e.g. after a braking event. It goes something like this:
- Cruise set to 70, but someone cuts in and I brake down to 50.
- Once I have enough space, I click "Resume"
- The car takes way longer to accelerate than the folks behind me will permit, and there's nothing but daylight in front of me, so I press the gas pedal until I'm at ~60.
- I let off the gas pedal to allow the ACC to take over; the Clarity slows down, with the throttle indicating dropping below 0 to "charging".
- Something like a full second later (which seems like an eternity) the ACC realizes it's going 10 under the set speed of 70, with no vehicle in range, and kicks the throttle up.
Ideally, the acceleration would just seamlessly move from pedal control to ACC throttle, but I have to hang on the accelerator much longer than I would intuit in order for that to happen.