Ward's Auto editors pitted a 2010 Toyota Prius against a 2009 Volkswagen Jetta TDI

Ward's Auto editors pitted a 2010 Toyota Prius against a 2009 Volkswagen Jetta TDI

Every August, executives from the world's auto industry gather in Traverse City, Michigan, for what's known as the Management Briefing Seminars. It's a mix of presentations, news, schmoozing (and, traditionally, golf) that ended yesterday.

This year, the audience was down by one-third over last year's 1,000 or so attendees.  There was less golf and a lot more anxiety. Some of last year's attendees, in fact, no longer have jobs.

To lighten things up, industry trade journal Ward's Auto did a little stunt: Editors Christie Schweinsberg and Tom Murphy drove from Detroit to Traverse City (about 200 miles) in two green cars, one hybrid and one clean diesel.

Their route had two legs; the first was on the Interstate, the second over two-lane rural roads. Speeds were kept to 70 miles per hour, and both cars started with full tanks and followed an indentical route.

The competitors were the all-new 2010 Toyota Prius hatchback, the third generation of the model that defined hybrid to the world (EPA rated at 51 mpg city / 48 mpg highway), and a 2009 Volkswagen Jetta TDI sedan (29 mpg city / 40 mpg highway), the latest iteration of VW's decades of small diesels.

The results, despite the Jetta TDI's higher-than-EPA real-world mileage, disappointed clean diesel fans. The Prius trounced the Jetta TDI, returning 48.3 miles per gallon on the first leg (vs the TDI's 39.5 mpg) and a stunning 60.1 mpg on the rural roads (against the Jetta's 44.0 mpg).

Note that these are all far better mileages than pretty much any other new car will give you today. And because MPG is not a linear scale, the actual gasoline saved over 100 miles by going from 40 to 60 mpg is less than 1 gallon.

While the hybrid won the fuel efficiency stakes, the diesel was the drivers' favorite for its abundant torque and sportier handling. The Prius has never been remotely sporty, whereas the Jetta is known as a sort of junior BMW 3-Series.

The Jetta zipped up twisty hills that the Prius's Hybrid Synergy Drive struggled with, while drivers behind the Prius seethed as its pilot struggled to keep her car out of "Power Mode," which sucks more fuel.

So there you have it: Sometimes higher fuel economy comes at the expense of driving quality. Care to weigh in, diesel fanboys?

2010 Toyota Prius

2010 Toyota Prius