The European market has many more small, fuel-efficient car models than we get in America, but even European versions of international cars like the Jetta are rated at higher MPG numbers. We can explain why.
This question came up when Consumer Reports slammed Ford's Ecoboost motors and downsized turbo engines in general. Reader Batman wondered if EPA testing is at fault, and if they are responsible for the MPG disparity across the Atlantic.
Why does a TDI Jetta in America struggle to make 45 mpg but a European TDI Jetta makes 65 easily?
VW owner K5ING stepped in to explain that Europe's MPGs aren't the same as our country-strong MPGs.
Part of that is that Imperial gallons are different than US gallons. 1 US gallon = .83 Imperial gallons. 45 US MPG = 54 Imp MPG. Or, 65 Imp MPG = 54 US MPG.
My Golf TDI gets right at 50 (US) on the highway, so it's right in the middle.
We would also point out that European cars don't go through the same tests as American cars do. The EPA's test attempts to mimic American driving conditions, while European cars go through a more European test. We're not exactly happy with the realism of either of the tests (and many car buyers aren't either), but they're sure to account for further MPG differences between European and American market cars.
So that roughly covers the difference between the two markets, but it leaves out a bigger issue, as pointed out by BLOZUP.
I blame it on MPG. What a horrid unit to measure fuel efficiency.
Liters per 100km (l/100km) is a much better measurement. It rates the amount of fuel needed to cover a set distance. This system points out that the biggest gains in fuel efficiency are relatively low down. Going from 25 to 35 MPG is, for instance, a much, much smaller change than going from 15 to 25 MPG.
For those curious, here's how to convert between the two measurements in your head. It's easy!
Photo Credit: VW