Fuel efficiency- Stop at red light, or lift off early and don’t stop?

I'm sure there was a fifth gear or top gear video about this. They had a Caterham (or similar) hooked up to half a litre of fuel and tried different driving styles around a circle to see which style got the furthest. Can't find a video but I'm sure this happened...
 
Jokester said:
Nothing wrong with that last one, especially if you had to stop whilst it was green!
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Maybe I've explained it badly. I'm talking about the person who is at the stop line - but rather than waiting for it to turn green and then setting off, keeps preempting the light change and just rolling forward a few inches before stopping again. The worst of the people who do this end up with their entire car over the line by the time the light actually does change.

To be honest, I can't quite place what situation you're talking about that is sensible behaviour. Unless you're talking about someone who as got caught in a jam in the middle of a junction when the light turned red?
 
bazzabear said:
Maybe I've explained it badly. I'm talking about the person who is at the stop line - but rather than waiting for it to turn green and then setting off, keeps preempting the light change and just rolling forward a few inches before stopping again. The worst of the people who do this end up with their entire car over the line by the time the light actually does change.

To be honest, I can't quite place what situation you're talking about that is sensible behaviour. Unless you're talking about someone who as got caught in a jam in the middle of a junction when the light turned red?
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No I'm talking about triggering the motion sensor to allow the lights to change back to green again.
 
As a rule of thumb, the less you use the brakes the more efficient it should be, although I guess with these modern KERS systems harvesting energy during braking the difference is less pronounced than it used to be.
 
Both of you are doing it wrong, stops at red lights should be approached gently then the brakes applied sufficient enough to allow the start stop to operate. I do this all the time so it is definitely possible.
Thus not only saving fuel but also allowing the start stop to do what it is intended to do and help in reducing pollution when stationary...
 
cuke2u said:
Both of you are doing it wrong, stops at red lights should be approached gently then the brakes applied sufficient enough to allow the start stop to operate. I do this all the time so it is definitely possible.
Thus not only saving fuel but also allowing the start stop to do what it is intended to do and help in reducing pollution when stationary...
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But you’re then using fuel to restart from Stationary, which may undo all the good you’ve done!
Unless you’re saying your stop start kicks in whilst the vehicle is in motion. My one doesn’t (Mercedes GLC).
 
bazzabear said:
Maybe I've explained it badly. I'm talking about the person who is at the stop line - but rather than waiting for it to turn green and then setting off, keeps preempting the light change and just rolling forward a few inches before stopping again. The worst of the people who do this end up with their entire car over the line by the time the light actually does change.

To be honest, I can't quite place what situation you're talking about that is sensible behaviour. Unless you're talking about someone who as got caught in a jam in the middle of a junction when the light turned red?
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and their reaction time when it finally goes green is like 3 seconds :p

glad my car doesn't have stop/start btw or I might have these thoughts!
 
cuke2u said:
Both of you are doing it wrong, stops at red lights should be approached gently then the brakes applied sufficient enough to allow the start stop to operate. I do this all the time so it is definitely possible.
Thus not only saving fuel but also allowing the start stop to do what it is intended to do and help in reducing pollution when stationary...
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Wrong. True efficiency comes from the driver who doesn’t stop…

that said my Insight below 18mph when slowing I can clutch in and it kills the engine to allow freer rolling coasting with no fuel.
 
Housey said:
The woman is always right. Please take this life lesson forward and thank me for the pain saved.

Say after me.. “yes my darling I’m sure you’re right”

it’s just gonna be easier!

And sorry for my horrific gender assumptions
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The generation gap in advice on dealing with a ltr is the true age divide.
 
Slowing up and rolling towards lights in gear is best for me. Instant consumption goes to 999mpg and if I drop to 3rd to build back up to 30mph keeping the revs low will be about 18-22mpg whilst accelerating.

If I stop completely I drop to around 12mpg when pulling from a stop and build through the gears.
 
Use gears to engine brake. Zero fuel use as the motion of the wheels "drives" the engine (no injection happens), and no brake pad usage because you're using the engine to brake not the brakes :P
 
Jonny ///M said:
Slowing up and rolling towards lights in gear is best for me. Instant consumption goes to 999mpg and if I drop to 3rd to build back up to 30mph keeping the revs low will be about 18-22mpg whilst accelerating.

If I stop completely I drop to around 12mpg when pulling from a stop and build through the gears.
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Wonder how accurate the instantaneous MPG read out is vs the reality - on my pickup it maxes out the range and is like 999 on OBD when rolling without acceleration input.
 
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