Petrol at one Michigan service station hit 47 cents (33 pence) a gallon last Sunday as a price war between local stations forced the owner to reduce prices to levels not seen in decades.
The sub-dollar level is unusual even in the US, where the average national price on Sunday was $1.89, according to the American Automobile Association.
But the steep drop in Michigan is indicative of the struggle engulfing the oil industry in the US and globally. Growing competition, excess supply and shrinking demand are forcing the price of oil to record lows.