Re: Power required
A hybrid generally does slow crawl stop/start urban driving on battery power. They are absolutely superb in these circumstances.
That experience on the A55 outside Abergele certainly showed that. I'd wondered what happened on really long delays when the battery had no chance of keeping the car going. From that experience it appears that Toyota have developed a very effective system. It looks like running the ICE at maximum efficiency to get energy into the battery then using the battery to propel the car is a very efficient way to propel the car at slow speed. Interesting that it chose to run the ICE at relatively low RPMs though. I'd have thought it'd go for 2,000 rather than 1,200.
It's a bloody boring and tedious way to drive past Abergele though :-/