So, It has been a whole year since I last posted - crazy!
Here is the rule of thumb regarding car idling costs and the ADDED benefit of cutting pollution. Engines consume gas while idling - in the range of 2-5 gallons per hour. When shut-down they consume ZIPPO. In a recent issue of Popular Mechanics in the "Car Clinic Q&A" the editor wrote "that's why hybrids and some new cars shut-down at traffic lights - to conserve fuel - restarting automatically when your foot comes off the brake so the car is ready to go by the time you get to the gas pedal." The misconception comes from the old days "when cars had carburetors and chokes, a cold start involved ...a few pumps of the accelerator" to get the engine going - which used a half-spoonful or so of gas. This old-school cold-start process seems to have bred a generalization about the starting process which does not jive with the physics of the present day fuel injected start. Bottom line, shut 'er down rather than idle for more than a few seconds.
See ya' at the Starbucks drive through with the engine off,