LOL!  I mean it takes some gut's to get up hill's right?  If you accelerate half way up it as opposed to having the momentum "before" and accelerating before you get to the hill, you end up using more gas.  Same when you break a lot too.  It is more efficient to let a car slow as you reach the traffic lights, as they may change to green and then it is just a case of accelerating from the speed you are at.  However, if you break and slow right down, you may slow the car to less than what you need to and have to accelerate more to get take off!  Well I think it is like this anyhow--especially with this damn Pajero---I hate to try to overtake as I have a two ton wagon loaded up with kid's and I sometimes my foot it literally to the board trying to accelerate.  So I tend to just not break as much and try to just glide into things slowly---without hitting someone of course. (And there goes my gas saving TIP of the day--LOL!)