"The three cars, with their 30 to 40 mph top speed and limited acceleration, would operate either on a paved road system of their own or in reserved lanes of existing roads, because they could not mix safely with today's freeway of boulevard traffic," GM said in a 1969 press release.
Each car had a different drive system. The blue car, the 512 Hybrid, was a gasoline-electric hybrid vehicle. The red car was an all-electric car and the yellow car ran on a 12-horsepower 19.6 cubic inch (0.3-liter) two-cylinder engine. The silver three-wheeled car on the far right was the gasoline-powered 511 Commuter Vehicle.
GM featured the cars in a 1969 media event called the "Parade of Power." The show highlighted the automaker's research into various forms of alternative propulsion. Also included were jet-powered cars, a steam-powered Pontaic Grand Prix and an exhibit on "nuclear reactor systems as possible means of powering vehicles."