I was intrigued by this so I pinged a friend at GM. Here’s what he said: “The vehicle in question is a development mule (no production intent) – one of the batch of 30 that the [Volt] engineering team was to test before they built the 80 pre-production [Volts] currently being used (and driven by you a week ago). Most of the mules have been released “from active duty”, but a couple are still being used for testing at [Milford Proving Grounds].”

My report on the Volt drive he refers to is here: http://bit.ly/6CdqIn