No one will ever look at the 2010 Toyota Prius without being able to recognize it as the world's most popular hybrid car. The distinctive Prius shape, sharply defined for the public by the 2004-2009 second-generation model, hardly seems to have changed at all. But changed it was, in ways both large and small. The 2010 Prius is more aerodynamic than ever, with a 0.25 coefficient of drag. That's as low as any car in the world that's in volume production. 30 Days of the 2010 Toyota Prius: Day 8, Body and Aerodynamics - All About Prius