As gasoline prices shoot through the roof and concerns over the effects of automobile exhaust pollution continue to grow, "Car Talk" co-host Tom Magliozzi sets out to replace his cherished 1952 MG roadster with a more environmentally friendly automobile. Along with his brother Ray, Tom explores the revolutionary technology that promises to change the way we drive. Along the way, Ray and Tom pay a visit to the world-famous North American International Auto Show in Detroit, speak with the organizers of Boston's AltWheels Festival, hitch a ride with a hydrogen-powered bus fleet in Iceland, and ponder the future with a green-leaning Colorado think tank. Are the rumors of an electric sports car that goes zero-to-sixty in just four seconds too good to be true? Find out the answers to this question and more as Tom and Ray speak with experts in lithium batteries and biofuels in order to separate the hopeful speculation about tomorrow's technology from the hard facts.