On the fuel efficiency of hybrids:

Hermance said drivers who slowly roll through intersections using "California stops" are decreasing their mileage. "If you don't stop, you don't get the free energy of regenerative braking."

Apparently those hybrid engines are more advanced than I realized. Somehow the energy stored by the regenerative braking system exceeds the energy that the moving vehicle had, by enough of a margin to improve its mileage.

The next paragraph attempts to explain this unusual (thermo)dynamic, but ends up making it sound like the car is just poorly designed.