Earlier quoted context omitted.
> At that price, gasoline would be about $18/gal and no one could afford to move anything except by ox cart. Just for some rough math here - I’m currently paying around $1.20/L for gas, and crude oil cost is roughly half of that, so if crude went up by 6x, I’d be looking at $5/L for gas. Gas is currently about 20% of my per-km cost of driving, so that price increase at the pump would increase my per-km cost by about…
How can you possibly say that crude is half of the pump price? The economics are incredibly complex and murky, and the price of gas doesn't move with any sort of linear relation to crude except in very long timeframes. Regional refining capacity is way more important.
Look at gas prices in your area. Look at the price of crude. Divide.
How could you possibly not be able to estimate the fraction?
And yeah ideally you use an average number over some months and you sample the crude earlier than the gas but those are minor tweaks.