Double deck LPG busses are used by highly populated urban cities. It doubles the capacity and reduces space by half. Plus, the design can be modified for rain flooded streets like cebu city. Do this by raising the engines.
Save the billions... build bus loading areas that don't obstruct traffic flow. Clear and Widen the sidewalks. Provide side walk canopies for pedestrians.
Money saved can then be used for a MTR system.