Looks like he's got the right idea though - always driving downhill like that.
Seriously, you see why the small, new, very clean diesel, is becoming more popular.
I drive one of the quiet newer diesels, and they're great. American car makers have done stupid things with diesels in the past (like trying to make a 327 block Chevy engine, into a diesel block (GM), using cheap sensors(Ford and Dodge)), but their latest offering are much better. They're finally accepting help from diesel engine specialists, which was long overdue.
Stop and go driving, diesel mileage will drop a lot, but once at a steady cruising speed - diesel's really know how to sip on fuel.
Congratulations to our builder!