The document summarizes three bus transport designs: normal, low carbon, and no carbon. The low carbon design uses half the engine volume and fuel compared to normal but maintains the same tonnage, horsepower, and speed. It saves 72,000 liters of fuel per year. The no carbon design uses compressed biogas and saves 144,000 liters of fuel annually. Both low carbon and no carbon designs increase revenue by reducing fuel costs while maintaining a fare of 1 cent per kilometer. The low carbon design provides an 82.91% return on investment and the no carbon design provides a 36.75% return.