The Mercedes-Benz Vision EQXX Concept glides along the track at the company's Immendingen Test Center in southeastern Germany like it's been in development for years, rather than 18 months. Such a short gestation for a concept car is not unusual, but the EQXX is not your typical concept.

More a rolling test bed draped in the fineries of an auto show debutant rather than your typical fragile, hand-built concept, the Vision EQXX previews the future technology and philosophy of Mercedes' electric vehicles. Last month, the EQXX completed its second ultra-long-range, single-charge journey. That 728-mile trip from Stuttgart, Germany, to the UK's Silverstone Circuit bettered a 621-mile drive in April from Sindelfingen, Germany, to Cassis, France.

And now I was taking it on two 10-mile jaunts around the Immendingen facility. For anyone that thought extreme range demanded extreme sacrifices, the effortlessly refined and rich EQXX says otherwise. At the same time, Mercedes has proven that current mass-market EVs have barely scratched the surface of electric efficiency.