UPS is known for its amazing level of efficiency, and that reputation could soon extend to fuel savings thanks to a prototype dubbed CV-23. The delivery company has ordered five of these prototypes to be tested through the end of 2011, but this is no ordinary next-generation package hauler.The CV-23 weighs about a thousand pounds less than the typical UPS truck, thanks to the fact that it is made with composite materials instead of metal. The lightweight materials could help UPS deliver up to 40 percent better fuel economy than the current UPS fleet truck. Those kinds of fuel economy gains can pay huge dividends in rural areas where trucks are required to drive large distances. And since the body panels are plastic, bumpers, panels and other parts can be replaced easily. Hit the jump to watch video of the CV-23 as it is tested by UPS management. If the company is sufficiently impressed, the guys and gals in brown could order more trucks, potentially saving 84 million gallons of fuel per year. We're guessing drivers will want to see some crash test data before seeing what brown plastic can do for them, but otherwise, this seems like a pretty good idea.