And to those who don't think sitting stationary adds up over time: my 2013 car, with 61k on the clock, has had iStop engaged for 76 hours.
While I'm sure that does amount to a decent amount of fuel over that time, the downside is certainly the impact this has on the battery - when I had to replace it a few years back I recall the cost was ridiculous compared to a bog-standard battery. Mazda was going to charge something like $800, but a terribly helpful chap here on GZ sold me one via his company for way, way less.
Sure hoping this new battery's not needing replacing already!
I wonder with these iStop type features how much the starter motor's life is shortened. I seem to remember Toyota back in the 1980s having this feature but dropped it because of starter motor failures.