機関長
In 1999, Toyota began development on a second generation Prius under chief engineer Shigeyuki Hori. In 2001, Hiroshi Okamoto's exterior design was approved and frozen for production. In 2003, the Prius was completely redesigned as a compact liftback, with redistributed mechanical and interior space significantly increasing rear-seat legroom and luggage room. The 2004 Prius is even more environmentally-friendly than the 1997–2003 model (according to the EPA), and is longer than the previous version. Its more aerodynamic Kammback body balances length and wind resistance resulting in a drag coefficient ( "C""d") of 0.26. Chief engineer Shigeyuki Hori's development effort led to 530 patents filed for the vehicle.