The majority of people in the US live in urban and suburban areas. There’s plenty we can do in these areas to reduce car-dependency instead of paving more roadway (which ends up as waste of time due to induced demand).
The correct comparison should be comparing for each area and situation, which type of transport investment results in the greatest utility. The objective is not to minimise traffic, but to maximise peoples ability to get where they need to be.
But, many studies have shown that building more roads does not reduce congestion. Congestion is not function of roadway space-- other factors like accidents, merging, exiting, peak travel capacity, etc greatly impact congestion. Building another lane on a highway doesn't solve the problem.