President Barack Obama, with Assembly Manager Teri Quigley, drives a new Chevy Volt, during his tour of the General Motors Auto Plant in Hamtramck, Mich., July 30, 2010.

President Barack Obama, with Assembly Manager Teri Quigley, drives a new Chevy Volt, during his tour of the General Motors Auto Plant in Hamtramck, Mich., July 30, 2010.