# Couple trapped in car for 13 hours: AKA common sense WTF

• Your wallet must hate you

But the taxman loves him!

• Meh. At absolute worst (20p/litre more) it makes like Â£11 difference per tank, and even at a tank a week, that's nothing in the grand scheme of things.

• But the taxman loves him!

He gets way more from my pay than he does from my diesel habit.

• That's four pints a week though!

• I don't fill up at 20p/litre extra every week.

• I don't fill up at 20p/litre extra every week.

HOW WERE WE SUPPOSED TO KNOW THAT? WE'RE NOT FUCKING PSYCHICS!

• WE'RE NOT FUCKING PSYCHICS!

You want him to summon his fÃ¦cal matter to a court of law?

• You want him to summon his fÃ¦cal matter to a court of law?

Blah blah dumb shit blah blah stop reading words I didn't write blah blah.

Sorry, that only registered 34 milliBlakeys

• I'm just bored.

• Hell, the driver adds more weight than the fuel!

Solution: Don't get in your car when you want to drive somewhere as it's bad for the car's gas mileage.

• Given a typical fuel tank size of 45l, and assuming 1l fuel = 1kg (it doesn't, but it's close enough for this), that's, at best, saving about 40kg. Even the smallest cars weight around 1000kg; a full tank is a 4% weight change, which does almost nothing. Hell, the driver adds more weight than the fuel!

Also, most likely, you burn more fuel driving to the petrol station that often than you burn lugging the extra petrol around and just driving till empty.

• Solution: Don't get in your car when you want to drive somewhere as it's bad for the car's gas mileage.

Problem: Unable to use vehicle because not currently in it

• WONTFIX: vehicle has NaN miles per gallon, which is not less than or equal to your previous MPG.

• Some people keep their tanks low on the basis that it costs more to haul the extra weight of fuel.

My Fusion Hybrid gets much better fuel economy on a full tank than an empty one, I've noticed. I have no clue why. Magical elves, is my guess. Not the boring Lord of the Rings, but the kind who are tiny and make cookies.

• I used to do that, too. However, as a friend pointed out to his college-age kids many years later, even if you can only afford to buy \$X worth of gas at a time, it doesn't cost any more to go from full-X to full than it does from 0 to X, and you're a lot less likely to get stuck on the side of the road if you can't refuel when you need to.

This is ignoring the time value of money. Yes, it does cost more to keep the tank full than to keep it low, because you have to pay to get the tank full in the first place. You could be earning interest on that hundred dollars, instead.

Seems pointless? Imagine running a fleet of thousands of cars...

• Seems pointless? Imagine running a fleet of thousands of cars...

People in charge of fleets of cars aren't encouraging their employees to keep the tank low to 'save' money. Because it doesn't. And it also costs extra time for, say, 3 part-fills a week vs a complete fill a week.

• Because it doesn't.

It does. Time value of money. Or do you deny that you could earn interest?

Also, carrying around weight. Or do you deny that gas has mass?

And it also costs extra time for, say, 3 part-fills a week vs a complete fill a week.

This only enters into it if you need 3 part-fills a week. Lots of fleets are used to drive to a place and stay there for 4 or 5 hours at a time.

But a fleet manager would, you know, part-fill the underground tanks when appropriate instead of sticking hundreds of thousands of dollars worth of capital in there to depreciate.

• Also, carrying around weight. Or do you deny that gas has mass?

Right but those Maths have been covered. It's an insignificant difference.

Or do you deny that you could earn interest?

No.
But while you're considering the time value of money, consider the money value of time. A bit of extra interest vs more time spent putting fuel into cars.

• Iran out of fuel 3 or 4 times on that shitty scooter

Nearly every motorcycle I've owned didn't have a fuel gauge. I just reset the trip odometer every fill up and knew how many mile a tank should go. Never ran out of gas doing it that way.

• But while you're considering the time value of money, consider the money value of time.

It's always important to look at both sides of that, and so few people do. Or rather they do when they're thinking about their own life â€” people pay for a bit more convenience all the time â€” but they much less frequently do so when looking at anyone else.

• . I just reset the trip odometer every fill up and knew how many mile a tank should go. Never ran out of gas doing it that way.

That's the way I normally do it since fuel gauges are notoriously short on bikes even if they have them. Like I said, though, this bike didn't have a working odometer (or even speedo)

• Nearly every motorcycle I've owned didn't have a fuel gauge. I just reset the trip odometer every fill up and knew how many mile a tank should go.

Every car I've ever owned has had an accurate fuel gauge, yet I still use the trip computer to know when to refuelâ€¦

• You should also fill up at night when the cold means you get more mass of fuel per litre. Just before midnight if prices are rising (in case the price goes up at midnight) and just after if it's falling.

Usually around here the price changes during the day rather than midnight. And it's coldest just before dawn!

Growing up the price would remain constant for weeks, still the case in that city. But now I've moved to the "Big Smoke" the price can fluctuate over 15c/L in the cycle. It used to be Wednesdays that the price would jump up and then gradually drop. So Wednesday morning was my fill-up. But now the cycle is much more random.

Letting my first cars run dry was also laziness and optimism, I haven't let it get that low in years, even try and avoid the warning light appear. It didn't really matter when it was only me but now with children can't let them be stranded.

• @ben_lubar said:
Solution: Don't get in your car when you want to drive somewhere as it's bad for the car's gas mileage.

Problem: Unable to use vehicle because not currently in it

Secondary problem: unmanned vehicle careening wildy through the neaby area.

• Problem: Unable to use vehicle because not currently in it

So ... You're on it?

• Secondary problem: unmanned vehicle careening wildy through the neaby area.

Tertiary problem: Unable to do anything for the forseeable future due to imminent intervention by police forces

• Iran out of fuel

Citation please ... all figures I find don't see indicate that Iran is still has surplus and is still exporting oil.

• all figures I find don't see indicate that Iran ...

You seem to have a couple of extra words in there.

• Iran is still has surplus

Found another extra word. Do I win anything?

• You seem to have a couple of extra words in there.

Maybe he missed a word and a letter?

all figures I find don't seem to indicate that Iran ...

• Holly Molly I can hardly understand that sentence myself ...
Let's try that again ...

all figures I find indicate that Iran still has a surplus and is still exporting oil.

• This is ignoring the time value of money. Yes, it does cost more to keep the tank full than to keep it low, because you have to pay to get the tank full in the first place. You could be earning interest on that hundred dollars, instead.

Seems pointless? Imagine running a fleet of thousands of cars...

I've never bought that "cost of money" argument for operating expenses (maybe it would work for capital expenses).

Assume a fleet of 1000 cars driven an average of 150 km/week at 15 kpl. You'll pay for 10,000 L per week on the average, no matter what strategy you use. Every single week, you're either paying for 10,000 L for last week, or for this week, or for next week.

You might have held on to that money the first week and gotten the interest, yes, but after that, you're not getting that savings back until you sell off the fleet. Even if that happens decades later.

You might obtain price advantages by waiting, but that's a different subject.

• Holly Molly

Filed under: she's a hell of a gal

• You might obtain price advantages by waiting, but that's a different subject.

In all likelyhood you'll lose money because the price of fuel usually only goes upwards (disregarding recent tends).

• We all know how this is going to get fixed: Bigger decals!

Seriously, this is another WTF.

• We all know how this is going to get fixed

With a dirty car? Seriously, I don't want to see anything else of the interior of that car. It might has well have a raccoon living in it.

• Holly Molly I can hardly understand

Is that anything like a holly jolly Christmas?

• a holly jolly Christmas

I don't do those fancy modern holiday things

• I don't do those fancy modern holiday things

Oh, you're old school--more into the Mesopotamian gods, eh?

Anyway, the word(s) you were looking for is probably "holy moly" or "holey moley" or some combination thereof.

• Assume a fleet of 1000 cars driven an average of 150 km/week at 15 kpl. You'll pay for 10,000 L per week on the average, no matter what strategy you use. Every single week, you're either paying for 10,000 L for last week, or for this week, or for next week.

You realize you're describing the difference between annuities immediate and annuities due? The difference in their value is exactly the interest earned in that first period, multiplied by the annuity amount. If we're talking 40,000 L a month, that could be on the order of \$2000 for negotiating an arrears payment plan instead of an advance one.

Also, consider the effect of excess capacity. Your gas filling station can handle, say, 30,000L (or 120,000, so it will last for 90 days). How much should you buy? Your total capacity is effectively a "real option". Put into the language of vanilla options, you should buy as much as you can when the "dividend" (i.e., the saving incurred by owning) exceeds the financing cost of buying.

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