The Peugeot compressed air idea has an appeal. Autocar had an in depth (yes, really!) write up on progress so far a few weeks back. Have to say was impressed. I see Mercedes / Mitsubishi trucks have a Canter 7.5 tonner with hybrid battery tech under evaluation, so it is spreading........
And with regard to saving the planet- I was waiting at the rail station few weeks ago during a cold spell and a Prius arrived with driver and passenger. It then sat in car park for good 10 minutes with engine running, obviously to keep the occupants warm.
