Should We all Use Pence Per Mile To Compare Efficiency

Currently reading:
Should We all Use Pence Per Mile To Compare Efficiency

Should We Use Pence Per Mile To Compare Efficiency


  • Total voters
    2
Joined
Oct 18, 2023
Messages
190
Points
143
Location
Folkestone, Kent
We fill up at the pumps in ltrs, and we pay in pennies, what could be easier.
IMO pence /mile makes more sense.
It seems odd to still be using MPG, when nobody in the UK or europe uses gallons any more.
I fill up reset the trip , and get value from my receipt. Pennies divided by miles gives me the cost per mile.

In mainland Europe, they could just substitute km for miles.
 
No, because your "efficiency" would change on a weekly basis right now and vary from region to region (or paterol station to patrol station).

So I fill up at £1.65 last week or week before., this week the same garage is £1.55, the cost per mile will be different, yet my car's the same efficiency.
 
I feel like it's one of the many measures you get on a new car in the showroom..or at least annual fuel bill is which you can divide by however miles they base it on.

Otherwise though true pence per mile would take into account depreciation, taxation, service costs, etc. etc.

At the moment it would favour EVs but ignore the chronic depreciation they are currently suffering, which given in most cases depreciation costs more than fuel until the car is older makes it unrepresentative.
 
Last edited:
No, because your "efficiency" would change on a weekly basis right now and vary from region to region (or paterol station to patrol station).

So I fill up at £1.65 last week or week before., this week the same garage is £1.55, the cost per mile will be different, yet my car's the same efficiency.

Ok, 'efficiency' was probably the wrong choice of word in this case, so lets swap it out for 'fuel cost', and yes, if the fuel price goes up then so does your running cost. The idea is to average the values obtained out over months, you'll soon see a pattern emerging.

There is no other really simple means to accurately compare fuel costs, using any car, and any fuel. (Using the method of setting trip meter after filling and noting mileage at next fill. After filling, then the the total price you just paid is the cost of the mileage you've just done.)

One thing I've learnt over the years using this method is that 56MPH is a universal speed for max fuel mileage, and the usage difference between driving hard and eco driving is nearly double.

When commuting to Dartford (for eight yrs), I tried every which way to lower my fuel costs, from slipstreaming lorries, to coasting down inclines, and it's amazing how much difference the weather made, if the wind was in your favour (or not), if it was raining, and you drove the entire journey with wipers on, when in winter & icy, the rear screen heater/headlights and accessories all on, the alternator was working flat out, all of which had a noticeable effect on 'pence per mile'.
 
There is no other really simple means to accurately compare fuel costs, using any car, and any fuel. (Using the method of setting trip meter after filling and noting mileage at next fill. After filling, then the the total price you just paid is the cost of the mileage you've just done.)
Or if you use the number of gallons used and compared that to the miles driven then you'd negate the pump price variations. If there was only some way to bring the gallons used and miles driven together.... then you'd be on to something.
 
Go back 2 years and I put £22 of Diesel in on a Saturday night and that got me through the week =@250 miles

Now got a petrol 500..smaller.. And it's £15 twice a week

Doesn't make much sense to me

The continental..
How Much Fuel to cover a set distance isn't a terrible idea

7 litres per 100 kms = thirsty
4.5 litres per 100 kms =. Better
 
When commuting to Dartford (for eight yrs), I tried every which way to lower my fuel costs, from slipstreaming lorries, to coasting down inclines, and it's amazing how much difference the weather made, if the wind was in your favour (or not), if it was raining, and you drove the entire journey with wipers on, when in winter & icy, the rear screen heater/headlights and accessories all on, the alternator was working flat out, all of which had a noticeable effect on 'pence per mile'.
Sounds expensive

o Following too close behind lorrys = paint & screen stone chips, dings and potential broken windscreen
o Coasting in at least Florida is an offence: 316.2024 Coasting prohibited.--The driver of any motor vehicle, when traveling upon a downgrade, shall not coast with the gears or transmission of such vehicle in neutral or the clutch disengaged.
o Driving with less than optimal lighting, whipers, etc. is like to get you clobbered by one of his majesty's boys in blue
 
Last edited:
Sounds expensive
o Coating in at least Florida is an offence: 316.2024 Coasting prohibited.--The driver of any motor vehicle, when traveling upon a downgrade, shall not coast with the gears or transmission of such vehicle in neutral or the clutch disengaged.
o Driving with less than optimal lighting, whipers, etc. is like to get you clobbered by one of his majesty's boys in blue
Leave Trump out of this.. 😉
 
Modern cars are less efficient when coasting, idle uses more than having engine braking since it shuts the fuel off.
 
Modern cars are less efficient when coasting, idle uses more than having engine braking since it shuts the fuel off.
But engine braking slows the car down more than coasting. If you don't want to slow down that quickly, then light pressure on the accelerator doesn't allow the fuel to be shut off and coasting should be more efficient.
There is a section of road, on my route home from work, when I will coast if traffic allows. This is a gentle downward slope, such that my vehicle speed barely changes whilst coasting down it, but in gear I would need to keep the accelerator lightly pressed to keep a constant speed.

The Highway Code does not forbid coasting but states the following:

Rule 122​

Coasting. This term describes a vehicle travelling in neutral or with the clutch pressed down. It can reduce driver control because
  • engine braking is eliminated
  • vehicle speed downhill will increase quickly
  • increased use of the footbrake can reduce its effectiveness
  • steering response will be affected, particularly on bends and corners
  • it may be more difficult to select the appropriate gear when needed.
On the section of road where I sometimes coast in neutral: engine braking is not required; the slope is not enough for vehicle speed to increase quickly whilst coasting; I barely need to use the footbrake (and the engine is running so vacuum assistance is preserved); and this is a dual carriageway with a gentle curve and no turnings, so steering response is not an issue and sharp turning would never be needed. In the very unlikely event that the engine cuts out (e.g. stalling due to low idle speed) stop-start would immediately restart it.
 
Last edited:
The only time I let the car coast is under 5mph, if you are above that then you should get done for it, plain and simple.
 
Coasting is not illegal, according to the "Rules of the road" as defined in the Highway Code, so I ask again: "for what offence" ?
 
I believe it's that you are not in full control of the vehicle
 
A retired judge made the point to me that the law is not perfectly black and white and much of it is open to different interpretations. He said "the law is what the judges say is". There is no clear statement on the legality of coasting, so it would probably depend on the judge's opinion, the conditions at the time and any accident or injury resulting from the driver coasting.

In my view, coasting is not illegal if the road conditions allow it, but some road conditions might make it illegal.

The offence of not being in proper control of a vehicle appears to be more about the position of the driver and whether they are deliberately distracted.
The Road Traffic Act 1988 (section 41D) states:
Breach of requirements as to control of vehicle, mobile telephones etc.
A person who contravenes or fails to comply with a construction and use requirement -
(a) as to not driving a motor vehicle in a position which does not give proper control or a full view of the road and traffic ahead, or not causing or permitting the driving of a motor vehicle by another person in such a position, or​
(b) as to not driving or supervising the driving of a motor vehicle while using a hand-held mobile telephone or other hand-held interactive communication device, or not causing or permitting the driving of a motor vehicle by another person using such a telephone or other device, is guilty of an offence.​
So there is no clear legal definition of not being in proper control, but typical instances might be (reference):
- Drinking something whilst at the wheel. Maybe a soft drink, coffee, tea etc.​
- Eating at the wheel. Maybe sweets, crisps or a banana etc.​
- Putting on that last minute makeup you didn’t have time to do at home before you left.​
- Map reading – this could be from a paper map or on an electronic sat nav system.​
- Using a mobile phone other than for making or receiving calls, e.g. looking at the sat nav system or choosing music to play whilst driving.​
Coasting does not seem to fit under this.

The Highway Code refers to (and defines) coasting and how it can reduce driver control, but does not use the terms 'must not', 'should not' or 'do not'.
So it is not made illegal by the Highway Code.

There are a broad range of driving offences which mainly fall under two categories: dangerous driving, and careless or inconsiderate driving.
Police advice is that (reference) :
The offence of dangerous driving is when driving falls far below the minimum standard expected of a competent and careful driver, and includes behaviour that could potentially endanger yourself or other drivers.​
Careless driving is committed when your driving falls below the minimum standard expected of a competent and careful driver, and includes driving without reasonable consideration for other road users.​
Some examples of careless or inconsiderate driving are:
  • overtaking on the inside
  • driving too close to another vehicle
  • driving through a red light by mistake
  • turning into the path of another vehicle
  • the driver being avoidably distracted by tuning the radio, lighting a cigarette etc
  • flashing lights to force other drivers to give way
  • misusing lanes to gain advantage over other drivers
  • unnecessarily staying in an overtaking lane
  • unnecessarily slow driving or braking
  • dazzling other drivers with un-dipped headlights
It could be argued that coasting comes under this category, dependent on the road conditions, but in the example I gave in post #12 I do not think there is any increased risk of endangerment.
 
Rules have changed subtly over the years from when I was tought to drive - rules that haven't really been well publicised in cases.
 
Back
Top