According to a group of researches at the Georgia Institute of Technology, pollution-free transportation is possible. While major projects in places like Europe are focused on using emissions-free technology at power plants to generate electricity, people from Georgia Tech are thinking about automobiles, transportation vehicles and industrial power generation applications (e.g., diesel power generators).
The team's target is creating a closed-loop carbon circuit system. This means burning a liquid fuel in the engine and trapping the carbon emissions at the tailpipe to be stored until the next refueling. At that point, the carbon would be transformed again into liquid fuel and reused to power the cars.
The researcher's current strategy is trying to capture carbon from gasoline (or any fuel) using a fuel processor to separate the hydrogen in the fuel from the carbon. The hydrogen will be used to power the vehicle and the carbon would be kept stored on board in liquid form. This process is not unlike DECARBit's project, to separate carbon before combustion. This rich-in-carbon liquid would be disposed at the fueling station and taken to a centralized site. First to sequester it (as explained here) or, as a long-term strategy, transforming it into another fuel.