Upcoming Frankfort Auto Show Featuring Green Cars.

FRANKFURT, Germany ? In closely guarded, advanced showings at the International Auto Show, environmentally friendly cars were the headliners Monday, with General Motors Corp. unveiling a new hybrid compact _ one among many vehicles at the show with advanced propulsion systems and cleaner engines. GM showed off its Flextreme from European subsidiary Opel, a small commuter car with an electric-diesel hybrid that can travel 34 miles on a single charge before switching to fuel. It is a concept car, meaning it may or may not go into production.