General Motors started building the first pre-production Chevrolet Volt electric vehicles today. The significant milestone marks the first time engineers are assembling a vehicle that looks like the car slated to start rolling off an assembly line next year.

These cars, known as integration vehicles, are key to the Volt's development because they are used to refine things like driving dynamics. They also get shaken down and beaten up to ensure the range-extended EV is road-ready. So far all we've seen are prototypes and test mules based on the Malibu and Cruze like the one we drove last month. The cars GM started building today at its technical center outside Detroit are the real deal.

"The purpose for the integration vehicle builds is two-fold," GM spokesman Rob Peterson told Wired.com. "First, they validate our production design, vehicle safety and performance capabilities. Just as important, the build activity provides valuable insight into the final vehicle assembly process to ensure a high-level of build quality and manufacturing efficiency when production begins in November 2010."

Engineers will assemble the first of the integration vehicles by hand, a process that will take about two weeks. Production will ramp up to a rate of 10 a week by mid-July, and Peterson says GM plans to have 80 cars on the road by fall. Early next year, GM will begin building "several hundred" more pre-production vehicles at the Detroit-Hamtramck Assembly plant that will produce the Volt we'll see in showrooms by the end of 2010.

Photo: General Motors