Environmental Quality and Existing Infrastructure

The Maze situation in California has brought up an interesting situation. In their attempt to get it done quickly, it seems as if they will waive the CEQA (California Environmental Quality Act) requirement in order to get the freeway rebuilt faster. It makes me wonder, why do we need to do laborious EI statements with light rail and streetcars that will be using existing roadways. It's not as if you're going to increase impervious cover or cause more pollution. Yes there are certain situations where extensive EIS should be performed but if a downtown circulator system is to be built in existing streets, why would we need a piece of paper to tell us what we already know? Am I way off base in thinking this?