My 2 cents. At least three things are at work here that give the UK numbers an advantage.
First, the mileage estimates in the UK are calculated using Imperial gallons, so they are already starting off with an advantage.
Second, many of the vehicles with those super high numbers are diesels. Some are tiny & most are turbo.
Third, the MPG numbers are WAY overly exaggerted. A quick look at Fuelly doesn't show me a staggering MPG difference with UK based vehicles. The numbers they come up with actually make the EPA look legitimate. (scary thought)
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