No-left-turns saves UPS $ -- Could Google save the planet this way?

I am clocking out of work to write this up. First this article from Wired:

No-Left-Turn Software Saves UPS a Bundle[by avoiding left hand turns] Lovell reports that UPS lopped off some 28.5 million miles from its delivery routes last year thanks to the software, saving 3 million gallons of fuel and cutting carbon dioxide emissions by close to 69 million pounds.

Could Google (and all the other map/directions providers) reduce gas use significantly by making their directions algorithms work a bit harder to avoid left hand turns? Similarly, avoiding hills is probably helpful. And a back road might be longer distance and even longer time, but if it keeps you driving steadily (instead of idling in traffic jams) and not going faster than 55 (when efficiency drops off), then it could be helpful.

Is fuel use even part of thier optimization for routing I wonder? I know that business class routing packages are very careful to minimize fuel costs (usually that is thier main purpose). Google Maps gives you a checkbox on directions to avoid highways. Could they give you a checkbox "save gas"?

I am linking to this post: Getting in the driver's seat which is tangentially related to gas prices in hopes of getting some kind of attention from Google. If not, oh well.

(Of course, I don't really believe anything like this could 'save the planet', but every little bit helps, and it made a good title)