Toyota Prius Plug In
The plug-in version of Toyota's highly successful Prius hybrid debuted at the Frankfurt Auto Show in 2009 in this file photo. Creative Commons

Toyota Motor Corp. (TYO:7203) was the first automaker to mass produce a hybrid, and the Prius remains the most popular one on the market even as competing brands are beginning to grab market share.

Now the world’s largest automaker is bragging that its Prius plug-in hybrid hit the equivalent of 581 miles per gallon on Germany’s famous Nürburgring Grand Prix-style race track, known as the “The Green Hell” for its challenging curves and steep climbs in the forests 75 miles northwest of Frankfurt.

According to a video posted Tuesday on Toyota’s YouTube channel, automotive journalist Joe Clifford ran the 12.9-mile loop almost exclusively on the car’s electric power, using gasoline only on the uphill climbs.

Granted, the Prius was decked out in weight-saving features from Toyota Racing Development, such as low-resistance tires and aerodynamic front and rear bumpers. Clifford also kept the average speed of his run to 40 miles per hour, making the loop in an agonizingly slow 21 minutes, more than three times longer than a typical run.

The purpose of the publicity stunt was to underscore the Prius plug-in hybrid’s ability to handle a commute using almost no fuel, at least by European standards, where people tend to drive more slowly and live closer to their jobs than Americans.

First introduced in 2010, the Prius plug-in hybrid is rated by the U.S. Department of Energy at 95 miles per gallon equivalent in combined city and highway driving. The U.S. rates the car’s range at six miles on electric-only power. A feather-footed driving practice called hypermiling can squeeze out extra efficiency by driving at a slow, moderate pace and coasting on hills.

Watch Toyota’s video here. Note that the mileage cited in the video is measured against imperial gallons (4.55 liters) not U.S. gallons (3.79 liters).