I should have been more specific - PHEV vehicles with significant battery capacity.
I think the Prius is something like a "traditional hybrid" or "mild hybrid" (I don't fully remember) which comes down to battery size and how exactly it moves the car.
My point is basically: modern PHEV hybrids are supposed to be used by charging the battery and filling the tank and their MPG ratings come from a carefully determined protocol of doing that, where as owners treat them as traditional/mild hybrids and just fill the tank.
I imagine that regen braking will push that battery charge up a bit but just doesn't overcome the added weight of the large battery plus motor, engine, transmission etc to get the really great MPG rating.
I think the Prius is something like a "traditional hybrid" or "mild hybrid" (I don't fully remember) which comes down to battery size and how exactly it moves the car.
My point is basically: modern PHEV hybrids are supposed to be used by charging the battery and filling the tank and their MPG ratings come from a carefully determined protocol of doing that, where as owners treat them as traditional/mild hybrids and just fill the tank.
I imagine that regen braking will push that battery charge up a bit but just doesn't overcome the added weight of the large battery plus motor, engine, transmission etc to get the really great MPG rating.