Luke Warner's blog

Should you let your car idle at a stoplight, or turn it off and restart when the light turns green?

A 30-second wait is enough to make it economical to shut down, The Department of Energy maintains that 1 million passenger vehicles idling 5 miuntes a day waste most of the 3 illion gallons of gasoline.  With cars of yore, it was sensible to let the engine warm up a little on a cold morning. Multigrade motor oil and closer engineering tolerances in newer cars mean tha this is no longer true.  So don't sit there getting zero miles to the gallon.