[maffyoo]

When see things like this, I always think of the Chinese proverb

"An inch of time is worth an inch of gold, but it is hard to buy one inch of time with one inch of gold"

Which always says to me that its not worth it just use the quickest option

Take the example drcongo posted:

"Yesterday I had to drive to a nearby town, just 20 minutes away, and noticed that every single petrol station there was a good 5p per litre cheaper than my town. I might plug this into a map."

Assume he uses 30 litres a week (high end of average UK usage) that's £1.50 per week saving but assume the extra miles use half a litre, that takes about 65 p off the saving (ill not go into wear and tear) over 30 years of work 50 weeks a year this means a saving of £1,275 over 30 years ... sounds a lot but

20 mins away - this assumes 40 minutes per week over 50 weeks is 2000 minutes, and over 30 years 60000 minutes. Now assume you are awake for 16 hours a day this equates to 62.5 days of free time - more than two months of awake time

so as the saying goes... which would you prefer £1,275 saving or 62.5 days of time

[entuno]

I almost never go out of my way for fuel, because as you say, it's rarely worth it once you factor in your time (never mind the fuel spent).

But it's still useful to know about price variation so that you can plan ahead. I regularly drive past several different petrol stations, and if I know that one of them is usually cheaper or usually more expensive then I choose to use or avoid it, or to decide that I'll fill up tomorrow when I'm going that way rather than today at a more expensive one.

And that'd be more useful built into satnav, so that if I know I have to fill up somewhere along my route then I can pick the cheapest place, since there's no real time cost to any of the options compared to each other.

[maffyoo]

totally agree, technology could make this much more cost effective (or time effective). what's the best use of my time versus the cheaper option..

It's interesting running the numbers though. e.g. if it only take 10 minutes to get cheaper fuel, how much cheaper does it need to be for your time to be worth more than the UK minimum wage (£12.21 for adults over 21)

based on my maths (from above calculations) it needs to be about 7p per litre cheaper to justify the extra 10 minutes and for your time to be worth more, per hour, than the minimum wage.

[maccard]

Sure. Now imagine your car’s GPS knows you have 60 miles in the tank, and your journey is 300 miles. It can query the APO and figure out what the best petrol station to refuel on your journey is.

More information is always good.

[citrin_ru]

Driving somewhere to fill the tank 5p/l cheaper probably waste of time but unless all your trips are very short you usually can find a petrol station along a commute roue or along the route of a long leisure trip which is cheaper than one closest to your home. When you see prices in your navigator it's much easier to do.

[mnw21cam]

Agreed. Most of the time the cost of driving out of your way exceeds the saving you would make. However, there's a fuel station near me that is 19.8% cheaper than one only 1.6 miles away from it, and that's a thing that is worth knowing.

https://xkcd.com/951/

[alias_neo]

As someone who waits until my tank is almost empty, to visit Costco one per month for a fill-up, despite it being 5 miles away, I understand your point.

However, I think (and hope) the point of this service is that by being public, it'll drive prices down for drivers.

I drive 10 miles round-trip once per month to save what I guesstimate is £5 on a tank of fuel, then spend £100-300 in the Costco store while I'm there. I'm not the target audience, but I hope that for those who drive regularly, or for a living, this can help route them to where they can get the best prices as they're passing by.

[balderdash]

It would be really nice if say apple maps on my phone when connected to airplay could get the Fuel level in my car and distance to empty, and then when you plug in a route, and press add a gas station to my route, it picks the best one based on time out of the way, how much fuel you have left, and best relative price. ideally you could set your preferences in the app (e.g. never more than 5min out of the way, below median price if less than 1/8 tank, lowest quintile price if >1/8 tank etc.

[MilaM]

Driving 40 minutes to save 5p might not be worth it. What does make more sense (at least where I live) is to go to the petrol station in the late afternoon or evening instead of the morning hours. The intraday price span on most regular fuels is usually 10 Euro cents per liter. Weekends also tend to be cheaper.

[Nursie]

That's an extreme case though, and not what this sort of thing is aimed at.

Here in Perth, Western Australia, it's common for pump prices to vary significantly even within a small radius. But they're all on https://www.fuelwatch.wa.gov.au/ so you can see what the price is ahead of time.

If it's 14c cheaper per litre (coming up for 10%) to go 500m one direction vs 500m another direction, which one are you going to choose?

[ksec]

>so as the saying goes... which would you prefer £1,275 saving or 62.5 days of time

Just want to say, nothing wrong with doing that. Everyone has different priorities. I just hope most wont have to do it.

[oniony]

I've also wondered about whether to fully fill my tank or drive on a small amount so that I'm not using fuel to carry fuel. Do you know of any metrics on that?

[embedding-shape]

I haven't made any calculations, and it's more a hunch, but considering you usually need to remove hundreds of KG in order to make an impact on how much fuel is being spent, 40-50L of gas (~40KG difference between full and empty maybe?) would have an marginal effect on how much fuel is spent to carry a full tank vs 10% filled tank.

Besides, with a smaller tank, you'll make more trips to tank it, and also have less choice to go to gas stations that are further away but have cheaper price. Then again it becomes a question of "Do I want more time or more money?", back to square one :)

Edit: Also, someone correct me if I'm wrong, but doesn't the fuel pump use fuel itself as a coolant or something? Never investigated myself, but some car-knower once told me that running the tank on low always isn't good for the fuel pump, or something like that. If that's true, running with 10% of the fuel would mean more maintenance too, potentially removing any savings in the first place.

[maffyoo]

you can probably work it out but you have to make a lot of assumptions :)

Ultimately how much is your time worth? in the example given drcongo's time is worth £1.28 an hour.

[fragmede]

Unless you're driving a lorry with a 120L tank, it's negligible. We're talking like, 100 mL per 100km.

[123pie123]

It can be more complex than that, sure for one person your comment makes sense

but if enough people use their time to go to the cheaper station further away, then they may force the closer garage to to reduce their price

either that or the close garage goes out of business and the one further away puts up the price because they can.

but still, it can be more complex

[Kinrany]

This is like saying that selling enough volume might make up for losing money on every unit. It's only complex until you do the math

[KellyCriterion]

Once I had a boss who said: "Availability beats Pricing, always"

[drcongo]

Well that saved me from trying to work it out, thanks!

edit: My annual milage is actually very low, so it definitely wouldn't be worth it, but I appreciated the maths either way.

[tialaramex]

If your priority is the journey to fill a car with fuel and time spent doing so, surely just buy a Battery Electric Vehicle and then this problem evaporates because it just plugs in like every other appliance you own rather than needing a trip to a fuel station.

Shopping around for the fuel of an EV you can do from a web browser, oh hey, Octopus have a good deal for night charging, click click done.

[teamonkey]

The typical use case is probably much more like deciding which station within half a mile of home is cheapest, and that could easily be a variance of 5p or more.

[delaminator]

You didn't factor in the amount of taxpayer money spent on creating the website and the ongoing costs of running it.