The BMW 520d is rated at 52 mpg (highway) in EU tests and 37 mpg city.
Christian Stampfer at The Diesel Driver drove the 520d from Munich to Frankfurt (apparently as part of alonger trip) and, while he didn't get 52 mpg at an average of 90 km/h, he did get an impressive 38 mpg overall.
The car isn't super fast but, with 0-100 km/h of 8.1 seconds, it's way faster than a typical hybrid.
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