Every bit helps. If you look at the Central Expressway (Bay Area) and compare it to Lawrence Expressway. Lawrence sits above, goes via an overpass and generate

Every bit helps. If you look at the Central Expressway (Bay Area) and compare it to Lawrence Expressway. Lawrence sits above, goes via an overpass and generates a lot of noise. Central, on the other hand had been lowered down. And lets smaller roads to pass over it. A lot less noise.