An epidemic of insanely slow drivers
Discussion
theplayingmantis said:
M4cruiser said:
Julian Scott said:
Julian Scott said:
They are IRL. I'll try to remember to photograph when I drive down tomorrow.
I know there was a google street image, but here was the NSL this morning:And in prophetic convenience, stuck behind the cars at just over half the speed limit:
And again 90 mins later on the way back:
But the other pictures - it's a Fiat Panda I believe! What do you expect!
You can't see past the wing mirror. Yet can see the lane in the immediacy and near distance is clear so surely you would position your self briefly to see past the wing mirror....
re: being a Panda, even the 90s versions can do a ton
KTMsm said:
Julian Scott said:
If you knew the road, with two cars to pass, uncertain as to how they may/may not speed up, it isn't.
Sorry but this just demonstrates that whilst you think the two cars ahead of you are poor drivers, some may think the same of youI'd highly doubt a Panda is significantly speeding up - if it does, abort the overtake but I'd be past in second gear before their brain has processed the NSL sign
Normally, yes, I'll be ready to punch past as soon as I can see the road, just before the NSL limit.
And back to the original point, it was how many people drive slowly....and specifically at half of a NSL speed limit. None of those drivers were driving poorly, just slowly.
M4cruiser said:
Smooth Driving: Avoid sudden acceleration and heavy braking. Smooth acceleration
Apparently, brisk acceleration is better because you achieve the desired speed more quickly and can cruise. I used to be a slow to moderate accelerator when doing hypermiling but from the cars I've driven, getting up to speed then rolling along seems to give better results whether on the motorway or stuck behind someone doing 20 in a 30. Try it. 
For my (automatic) TT, it can be the difference between 22mpg and 25mpg when driving in a 20 zone.Om said:
M4cruiser said:
Eco driving.
Example, from the web:
https://www.traveldevon.info/drive/eco-driving/
"Eco-driving is a driving style aimed at maximizing fuel efficiency and minimizing environmental impact. Here are some tips for eco-driving in the UK:
Smooth Driving: Avoid sudden acceleration and heavy braking. Smooth acceleration and braking can significantly reduce fuel consumption.
Maintain a Steady Speed: Try to maintain a steady speed whenever possible, especially on motorways and highways. Use cruise control if your vehicle is equipped with it.
Anticipate Traffic: Look ahead and anticipate traffic flow. This allows you to adjust your speed gradually rather than making sudden stops or accelerations."
With that in mind, I say again, what's the point in going past in that situation with the Panda etc? The writer already knows that section of road isn't long. You may save a minute.
Old fashioned means we didn't used to have any of this eco stuff. But we do now.
Nah - we have had eco-driving for at least the past 50 years. Get with the times Grandad!Example, from the web:
https://www.traveldevon.info/drive/eco-driving/
"Eco-driving is a driving style aimed at maximizing fuel efficiency and minimizing environmental impact. Here are some tips for eco-driving in the UK:
Smooth Driving: Avoid sudden acceleration and heavy braking. Smooth acceleration and braking can significantly reduce fuel consumption.
Maintain a Steady Speed: Try to maintain a steady speed whenever possible, especially on motorways and highways. Use cruise control if your vehicle is equipped with it.
Anticipate Traffic: Look ahead and anticipate traffic flow. This allows you to adjust your speed gradually rather than making sudden stops or accelerations."
With that in mind, I say again, what's the point in going past in that situation with the Panda etc? The writer already knows that section of road isn't long. You may save a minute.
Old fashioned means we didn't used to have any of this eco stuff. But we do now.
Hoofy said:
M4cruiser said:
Smooth Driving: Avoid sudden acceleration and heavy braking. Smooth acceleration
Apparently, brisk acceleration is better because you achieve the desired speed more quickly and can cruise. I used to be a slow to moderate accelerator when doing hypermiling but from the cars I've driven, getting up to speed then rolling along seems to give better results whether on the motorway or stuck behind someone doing 20 in a 30. Try it. For my (automatic) TT, it can be the difference between 22mpg and 25mpg when driving in a 20 zone.Hoofy said:
M4cruiser said:
Smooth Driving: Avoid sudden acceleration and heavy braking. Smooth acceleration
Apparently, brisk acceleration is better because you achieve the desired speed more quickly and can cruise. I used to be a slow to moderate accelerator when doing hypermiling but from the cars I've driven, getting up to speed then rolling along seems to give better results whether on the motorway or stuck behind someone doing 20 in a 30. Try it. For my (automatic) TT, it can be the difference between 22mpg and 25mpg when driving in a 20 zone.It may depend on how long you are then going to be "rolling along" after accelerating. If almost immediately slowing again, then obviously it would have been more economical to accelerate slowly/gently.
M4cruiser said:
If that were true then the government's advice would say so. They base their "driving" tips on huge experience by people such as the police drivers.
It may depend on how long you are then going to be "rolling along" after accelerating. If almost immediately slowing again, then obviously it would have been more economical to accelerate slowly/gently.
Did you not understand the BSFC map I posted above? I can explain if necessary.It may depend on how long you are then going to be "rolling along" after accelerating. If almost immediately slowing again, then obviously it would have been more economical to accelerate slowly/gently.
M4cruiser said:
Hoofy said:
M4cruiser said:
Smooth Driving: Avoid sudden acceleration and heavy braking. Smooth acceleration
Apparently, brisk acceleration is better because you achieve the desired speed more quickly and can cruise. I used to be a slow to moderate accelerator when doing hypermiling but from the cars I've driven, getting up to speed then rolling along seems to give better results whether on the motorway or stuck behind someone doing 20 in a 30. Try it. For my (automatic) TT, it can be the difference between 22mpg and 25mpg when driving in a 20 zone.It may depend on how long you are then going to be "rolling along" after accelerating. If almost immediately slowing again, then obviously it would have been more economical to accelerate slowly/gently.
bigothunter said:
Did you not understand the BSFC map I posted above? I can explain if necessary.
No, I didn't understand it, it's a completely unintelligible picture. But I wasn't going to say that unless you asked.What's BSFC anyway? (I know what BS normally is!)
But the point I made still stands, with or without colourful graphs. In this country (in the south anyway) if you get up to a faster speed you will almost immediately have to reduce it again. In which case you've used more juice than a slow acceleration to that lower speed.
Many years ago, Autocar ran back-to-back tests of a medium saloon car accelerating from 0-60mph to assess the fuel consumption over a measured distance under different acceleration techniques, Tests were repeated to ensure accurate results.
Initially they accelerated very gently changing gears at minimal engine speed. They repeated the test but focused on operating in the optimum area of the BSFC map: higher engine load and changing up at 3000rpm. Average speed during the second run was faster.
Fuel consumption significantly improved during the faster test. Accelerating slowly not only wastes time.
Initially they accelerated very gently changing gears at minimal engine speed. They repeated the test but focused on operating in the optimum area of the BSFC map: higher engine load and changing up at 3000rpm. Average speed during the second run was faster.
Fuel consumption significantly improved during the faster test. Accelerating slowly not only wastes time.
M4cruiser said:
bigothunter said:
Did you not understand the BSFC map I posted above? I can explain if necessary.
No, I didn't understand it, it's a completely unintelligible picture. But I wasn't going to say that unless you asked.What's BSFC anyway? (I know what BS normally is!)
Brake Specific Fuel Consumption often shown in g/kWh. It's a measure of the fuel efficiency of an IC engine. Absolutely fundamental to understanding driving techniques for lowest fuel consumption.
Please study the BSFC map and try to absorb what it's portraying, especially the optimum speed/load regions. 3D map is much easier to interpret than conventional 2D plots.
bigothunter said:
M4cruiser said:
bigothunter said:
Did you not understand the BSFC map I posted above? I can explain if necessary.
No, I didn't understand it, it's a completely unintelligible picture. But I wasn't going to say that unless you asked.What's BSFC anyway? (I know what BS normally is!)
Brake Specific Fuel Consumption often shown in g/kWh. It's a measure of the fuel efficiency of an IC engine. Absolutely fundamental to understanding driving techniques for lowest fuel consumption.
Please study the BSFC map and try to absorb what it's portraying, especially the optimum speed/load regions. 3D map is much easier to interpret than conventional 2D plots.
bigothunter said:
I was wondering what Birkenhead Sixth Form College had to do with it... Ref BSFC - what do the different colours mean?
The only bit that makes sense is this, which I already knew:-
"the highest fuel conversion efficiency is obtained at mid engine speeds and high load (torque)."
and essentially means that drivers who "labour" the engine (by changing up too early) are doing themselves a disservice, thinking it's more economical.
But - you are answering the wrong question.
You are comparing accelerating up to 60mph, either by doing it slowly over a fair distance, or by doing it quickly and then maintaining a steady 60mph for the balance of that distance. Yes, method 2 is likely to use less fuel.
In the real world, (like Alderley) I'm comparing (1) accelerating up to 45 ish and going a little up or down from there for the hazards/straight bits, with (2) your preferred method of going up to 60 then down to 40 for a hazard, then back up to 60 then down to 40 for the double bends, then back up to 60 then down to 30 for the next limit, all of which might save about 1 minute over the slower method, but is apparently justified by a pretty coloured graph.
It's obvious which uses more fuel.
The only bit that makes sense is this, which I already knew:-
"the highest fuel conversion efficiency is obtained at mid engine speeds and high load (torque)."
and essentially means that drivers who "labour" the engine (by changing up too early) are doing themselves a disservice, thinking it's more economical.
But - you are answering the wrong question.
You are comparing accelerating up to 60mph, either by doing it slowly over a fair distance, or by doing it quickly and then maintaining a steady 60mph for the balance of that distance. Yes, method 2 is likely to use less fuel.
In the real world, (like Alderley) I'm comparing (1) accelerating up to 45 ish and going a little up or down from there for the hazards/straight bits, with (2) your preferred method of going up to 60 then down to 40 for a hazard, then back up to 60 then down to 40 for the double bends, then back up to 60 then down to 30 for the next limit, all of which might save about 1 minute over the slower method, but is apparently justified by a pretty coloured graph.
It's obvious which uses more fuel.
M4cruiser said:
Ref BSFC - what do the different colours mean?
The only bit that makes sense is this, which I already knew:-
"the highest fuel conversion efficiency is obtained at mid engine speeds and high load (torque)."
and essentially means that drivers who "labour" the engine (by changing up too early) are doing themselves a disservice, thinking it's more economical.
But - you are answering the wrong question.
You are comparing accelerating up to 60mph, either by doing it slowly over a fair distance, or by doing it quickly and then maintaining a steady 60mph for the balance of that distance. Yes, method 2 is likely to use less fuel.
In the real world, (like Alderley) I'm comparing (1) accelerating up to 45 ish and going a little up or down from there for the hazards/straight bits, with (2) your preferred method of going up to 60 then down to 40 for a hazard, then back up to 60 then down to 40 for the double bends, then back up to 60 then down to 30 for the next limit, all of which might save about 1 minute over the slower method, but is apparently justified by a pretty coloured graph.
It's obvious which uses more fuel.
It all makes sense - you just don't understand it The only bit that makes sense is this, which I already knew:-
"the highest fuel conversion efficiency is obtained at mid engine speeds and high load (torque)."
and essentially means that drivers who "labour" the engine (by changing up too early) are doing themselves a disservice, thinking it's more economical.
But - you are answering the wrong question.
You are comparing accelerating up to 60mph, either by doing it slowly over a fair distance, or by doing it quickly and then maintaining a steady 60mph for the balance of that distance. Yes, method 2 is likely to use less fuel.
In the real world, (like Alderley) I'm comparing (1) accelerating up to 45 ish and going a little up or down from there for the hazards/straight bits, with (2) your preferred method of going up to 60 then down to 40 for a hazard, then back up to 60 then down to 40 for the double bends, then back up to 60 then down to 30 for the next limit, all of which might save about 1 minute over the slower method, but is apparently justified by a pretty coloured graph.
It's obvious which uses more fuel.
The colours indicate bands of BSFC. Best fuel efficiency is shown in black with a typical lower limit of 250 g/kWh (petrol engines). Drive poorly and it's possible to elevate that to over 600 g/kWh. So fuel consumption would increase by more than twice.
Have you read the explanatory link provided by cherryowen? https://x-engineer.org/brake-specific-fuel-consump...
You're right, I dislike dawdling at 45 mph. But as I mentioned earlier, if you have effective regenerative retardation typical of EVs and Full Hybrids, the fuel consumption penalty of accelerating/decelerating to/from 60 rather than 45mph is very small.
60mph used in the Autocar tests was chosen to match typical road speed. Clearly Autocar didn't anticipate bumbling along at 45mph which has become so popular now. But the test holds true for any chosen target speed whether 60, 45 or even 30mph. Accelerating on very light throttle is inefficient because low load (alias torque) is not an efficient operating point. This is shown by the BSFC map.
M4cruiser said:
Eco driving.
Example, from the web:
https://www.traveldevon.info/drive/eco-driving/
"Eco-driving is a driving style aimed at maximizing fuel efficiency and minimizing environmental impact. Here are some tips for eco-driving in the UK:
Smooth Driving: Avoid sudden acceleration and heavy braking. Smooth acceleration and braking can significantly reduce fuel consumption.
Maintain a Steady Speed: Try to maintain a steady speed whenever possible, especially on motorways and highways. Use cruise control if your vehicle is equipped with it.
Anticipate Traffic: Look ahead and anticipate traffic flow. This allows you to adjust your speed gradually rather than making sudden stops or accelerations."
With that in mind, I say again, what's the point in going past in that situation with the Panda etc? The writer already knows that section of road isn't long. You may save a minute.
Old fashioned means we didn't used to have any of this eco stuff. But we do now.
M4cruiser - using your eco-driving techniques, what typical fuel consumption do you achieve?Example, from the web:
https://www.traveldevon.info/drive/eco-driving/
"Eco-driving is a driving style aimed at maximizing fuel efficiency and minimizing environmental impact. Here are some tips for eco-driving in the UK:
Smooth Driving: Avoid sudden acceleration and heavy braking. Smooth acceleration and braking can significantly reduce fuel consumption.
Maintain a Steady Speed: Try to maintain a steady speed whenever possible, especially on motorways and highways. Use cruise control if your vehicle is equipped with it.
Anticipate Traffic: Look ahead and anticipate traffic flow. This allows you to adjust your speed gradually rather than making sudden stops or accelerations."
With that in mind, I say again, what's the point in going past in that situation with the Panda etc? The writer already knows that section of road isn't long. You may save a minute.
Old fashioned means we didn't used to have any of this eco stuff. But we do now.
Believe your car is a Toyota Avensis Auto.
bigothunter said:
Hoofy said:
M4cruiser said:
Smooth Driving: Avoid sudden acceleration and heavy braking. Smooth acceleration
Apparently, brisk acceleration is better because you achieve the desired speed more quickly and can cruise. I used to be a slow to moderate accelerator when doing hypermiling but from the cars I've driven, getting up to speed then rolling along seems to give better results whether on the motorway or stuck behind someone doing 20 in a 30. Try it. For my (automatic) TT, it can be the difference between 22mpg and 25mpg when driving in a 20 zone.M4cruiser said:
Hoofy said:
M4cruiser said:
Smooth Driving: Avoid sudden acceleration and heavy braking. Smooth acceleration
Apparently, brisk acceleration is better because you achieve the desired speed more quickly and can cruise. I used to be a slow to moderate accelerator when doing hypermiling but from the cars I've driven, getting up to speed then rolling along seems to give better results whether on the motorway or stuck behind someone doing 20 in a 30. Try it. For my (automatic) TT, it can be the difference between 22mpg and 25mpg when driving in a 20 zone.It may depend on how long you are then going to be "rolling along" after accelerating. If almost immediately slowing again, then obviously it would have been more economical to accelerate slowly/gently.
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