Time for change

There is no doubt that switching off the engine is better for any stop of 10 seconds or more. For most modern car engines this is true even for short stops of 5 seconds! In some countries you can get fined if you don't switch off the engine for short stops.

However, one thing is important: Don't press the gas pedal when you restart the engine. You should remove the foot from the gas pedal and only turn the key to restart the engine. The automatic engine management does the rest for you.

A Japanese study from August 2002 showed that on average you can save 13% of the fuel consumption in typical town traffic if you consistently switch off the car engine during stops of more than 5 seconds. For an average driver, the study showed fuel savings of more than 5% which also means that the carbon output would be reduced by more than 5%.

Unfortunately, I don't have the original Japanese study. I have only a report about the study in a Swiss newspaper (in German language). Some Web references are: 

• http://www.edf.org/documents/9581_Anti-Idling_FactSheet_April09.pdf
  
• http://sustainablechoices.stanford.edu/actions/on_the_road/turnoffengine.html

Best regards

Juerg