I had noticed that I never roll backwards on hills after lifting my foot off the brake (no brakehold activated). This morning I decided to test that on the steepest hill in town. I went halfway up the hill and took my foot off the Go pedal. It rolled slowly to a stop and then started rolling backwards (that, I didn't expect) so I hit the brakes to stop. Surprisingly, when I lifted my foot off the brake, it did not roll backwards at all. I want to emphasize this is without brakehold activated. Thus, the Clarity is programmed to be very safe on hills. Just remember to apply the brakes normally as you would on any other car.
You've discovered Honda's Hill-Start Assist. Neither the Owners Manual or Guide describe Hill-Start Assist, but it's listed in the specs of both the base and Touring models. It takes effect when you use the brakes to come to a stop on a hill. The Owners Manual (page 101) says not to use Brake Hold on steep hills (but wouldn't Hill-Start Assist always be in effect even if you've pressed Brake Hold?): Never use the automatic brake hold system or rely on it to keep a vehicle from moving when stopped on a steep hill or slippery roads.
I did read about hill start assist in the owners manual and then tried it out. I hadn’t noticed it before. On a really steep hill I stopped with brake hold, but the car started slipping back. I had read about this so I wasn’t surprised.
Thanks to your clue, I finally found it in the Owners Manual on page 379. I'd been searching for "hill-start assist" but there's no hyphen.
