Homemade Hybrids - with the 10-Second Rule →
https://marco.org/2007/03/30/homemade-hybrids-with-the-10-second-rule
It’s a myth that starting modern cars uses a lot of gas. Apparently, when you’re idling for more than 10 seconds, it’s better to turn off your car. This isn’t a huge surprise: for a while, UPS has required drivers to turn off trucks when making every delivery to save on fuel costs.