Who would've thought that the trickiest part of the Chevy Volt launch would turn out to be how to rate its fuel economy? Nonetheless, that appears to be the track were on ahead of the Volt's official release in November.

Over the past couple of years, the Volt has undergone hundreds of thousands of miles of driving tests, crushing, water dunking, extreme heat, extreme cold, revisions and tweaks. After all that testing, one thing is clear: the Volt is a solid car. Even more impressive is that all that testing and revision is plainly available for anybody with an internet connection to see. In fact, for presenting the most transparent car development process the globe has ever seen, GM deserves beau coup credit.

Yet there's still one niggling little detail to be fleshed out. If you remember about a year ago, GM came out with a claim that the Volt would be rated by the EPA at 230 mpg. It was an announcement that was immediately lambasted by the media and even EPA told GM to take their claim and shove it. GM quickly stepped down from the claim and has been reticent to even discuss fuel economy ever since.

But at some point they will have to come out with a number. After all, we live in a society that craves comparison, and how can we ever expect potential EV or Plug-in Hybrid buyers to know how much money they're saving at the pump unless they have a metric by which to compare it? Sure, sure... the more savvy among us can do those kinds of calculations ourselves... but put yourself in your average grandma's shoes (no offense grandma) and you quickly see how important some kind of energy efficiency metric is.

So what's taking so long? In this case, it's not even GM's fault; the EPA has been dragging their heels on the issue because, well, it's a complicated problem. Or perhaps EPA is just making it more complicated than it needs to be? In a sign that GM may be getting frustrated with the pace of the decision process, Micky Bly, executive director of global electrical systems for GM, told USA Today that GM has no clue what the new number is likely to be.

Even more curious is the fact that Tom Stephens, GM's vice chairman of global product operations, further told the media organization that the fuel economy dance with the government will probably continue until the "very eve" of Volt production in November, adding, "We've been working collaboratively with the EPA and the industry to come up with a number that gives our customers something they can feel comfortable with."

Right now there's virtually no agreement on how to rate mile per gallon equivalents for plug-in vehicles. In fact, there are some that say we should abandon the mpg metric altogether. Either way, these are numbers that will be very important for the eventual acceptance of plug-ins beyond the initial early adopters, so it's important that it means something and doesn't simply get lost in the complexity of regulatory- and engineering-speak.

What do you all think? Is there an easy way to solve the problem that makes all the stakeholders happy?