On 05/01/2017 21:07, Jeff Layman wrote:

I wonder. I assume you are referring to cutting the engine when stopping
at lights, etc. Sure, it must save fuel, but how much?

Tiff Needel on Fifth gear did a test in town driving (lots of lights
congestion etc) and got the result that it saved north of 1% (exact
figure eludes me). So worth having on a 'city car'.

Friend of mine's is a driving instructor his car has this auto engine
off feature he reckons it's a god-send for his type of driving (lots of
stationery to explain things) and reckons it can save him up to 10% on
his fuel bills